| US 7,588,702 B2 | ||
| Method of quenching electronic excitation of chromophore-containing organic molecules in photoactive compositions | ||
| Craig A. Bonda, Winfield, Ill. (US); and Anna Pavlovic, Elmwood Park, Ill. (US) | ||
| Assigned to Hallstar Innovations Corp., Chicago, Ill. (US) | ||
| Filed on Jan. 30, 2008, as Appl. No. 12/22,758. | ||
| Application 12/022758 is a continuation in part of application No. 11/891281, filed on Aug. 09, 2007. | ||
| Prior Publication US 2009/0041847 A1, Feb. 12, 2009 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. F21V 9/04 (2006.01); F21V 9/06 (2006.01); G02B 5/22 (2006.01); G02B 5/26 (2006.01) | ||
| U.S. Cl. 252—589 [424/59; 424/60; 424/401; 514/520; 524/90; 558/410] | 12 Claims |
1. A method of increasing the UV absorbing life of a sunscreen composition containing (a) a dibenzoylmethane derivative that
reaches a singlet excited state or fluoresces when exposed to UV radiation and (b) a cinnamate ester comprising adding a compound
of formula (I) in an amount effective to quench the singlet excited state energy from the dibenzoylmethane derivative and
transfer the singlet excited state energy from the dibenzoylmethane derivative to the compound of formula (I) thereby returning
the dibenzoylmethane derivative to its ground state so that the dibenzoylmethane derivative can absorb more photons from ultraviolet
light before it undergoes a photochemical reaction destructive to its UV-absorbing capability thereby photostabilizing (a)
and (b)
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