HallStar has created a polyester that allows formulators to combine active ingredients that have previously been considered too photo-unstable to be effective. Polycrylene S1 (Proposed INCI: Polyester-X (X is an Integer) not only photostabilizes avobenzone, but also enhances the water resistance of sunscreen products.
The photostabilizer replaces polycrylene's triplet state-quenching chromophore with one that also provides singlet state quenching, making for faster, more powerful photostabilization of sunscreens.
The polyester is most effective in combination with other photostabilizers. As with ethylhexyl methoxycrylene, polyester protects against loss of absorbance much faster than octocrylene. It is recommended at 1-5% in beach and daily wear products in spray, lotion, cream, balm and gel forms. It appears as a clear to slightly opalescent viscous yellow-gold to golden-tan liquid with mild, characteristic odor.