Esschem

Henry M Justi

Susan C Sheariss

George F Cowperthwaite

In the disclosed method for the reshaping (adornment, repair, covering, prosthetic extension, etc.) of essentially rigid, keratinaceous surfaces such as nail plates with a free radical-polymerizable acrylic ester, the free radical initiator comprises a compound of the formula III ##STR1## wherein R.sup.1 through R.sup.4 are hydrogen, an aliphatic group, an aromatic group, a cycloaliphatic group, or, less preferably, a sulfhydryl group, an alkali or alkaline earth metal salt of a sulfhydryl group, a halogen, or amino group; or R.sup.3 or R.sup.4 can be an alkali metal or alkaline earth metal cation when the 5-carbon is negatively charged. The compound of formula III, in chemically-curable systems is utilized in combination with a metal salt cocatalyst and, optionally, an organic buffering compound and a crosslinker. In light-curable systems, the compound of formula III has some photosensitizing properties but is preferably used in combination with a second photosensitizer which is effective when irradiated with light having a wavelength of at least about 400 nm. These curable compositions are preferably free of organic peroxides, aromatic amines, and inorganic fillers and pigments.

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Bryn Mawr, PA, United States of America

Henry M Justi