| abstract |
Novel polysubstituted 2-keto-1,4-diazacycloalkanes are powerful stabilizers for materials subject to ultraviolet (UV) light degradation, particularly for polyolefins. The cyclic 2-keto compounds of this invention have (a) a fixed two-carbon bridge between the N 1 and N 4 atoms of the diaza ring, the remaining portion of the ring having a variable length bridge of two or more carbon atoms, (b) and N-adjacent carbonyl in the fixed two-carbon bridge, and (c) at least one N 4 -adjacent carbon atom of the diaza ring is polysubstituted, that is, has two substituents which may be cyclizable. n Compositions containing (a) the polysubstituted 2-keto-1,4-diazacycloalkanes of this invention, and (b) prior art polysubstituted 2-keto-1,4-diazacycloalkanes, exhibit excellent stability to UV light. |