Unilever inventors have a new sunscreen invention that, according to a recent patent, is capable of minimizing cost and UV filter exposure while maximizing efficacy.
Various preparations have been crafted to precent or protect the skin against UV. Organic sunscreen agents of the dibenzoylmethane class are especially useful to absorb UVA rays. Due to their mode of action, however, they are rendered unstable after time. Many UVB filters also can be used, and as such, both UVA and UVB sunscreens are used to cover the entire range of UV radiation.
Yet another approach is to include inorganic zinc oxide or titanium dioxide, which physically blocks UV from reaching the skin and/or scatters incident solar radiation. While this approach acts across the spectrum, these ingredients appear white on the skin.
So, to achieve high-SPF sunscreens with acceptable aesthetic properties, it has been necessary to include high amounts of organic sunscreens; i.e., levels higher than 8% or even 12% are generally required to reach an in vitro SPF of 15 or greater. But this not only adds to the cost of the product, it exposes consumers and the environment to higher levels of active.
In response, the present inventors sought alternative approaches to provide high SPF protection at low sunscreen concentrations by leveraging polymers and structures of cosmetic bases. The key, they found, was specific classes of polymers that, when included in a base comprising a selective amount of fatty acid, provide enhanced sun protection.
Sunscreen composition comprising fatty acid and nonionic linear polymer
European Patent EP2938320
Publication date: Sept. 12, 2018
Assignee: Unilever N.V. and Unilever PLC
Disclosed in this patent is a sunscreen composition comprising: a) 0.1-5.0% of a UVA sunscreen; b) 0.1-10.0% of a UVB sunscreen; c) 0.1-10.0% of a nonionic linear polymer having a molecular weight higher than 8,000 and HLB value from 7 to 18, selected from the group of: polyvinyl alcohol, modified cellulose and poly(propylene oxide-co-ethylene oxide); d) 4-25% fatty acid; and e) 40-80% water. Furthermore, the UVA sunscreen comprises a dibenzoylmethane, triazine or triazone derivative; and the nonionic linear polymer comprises polyvinyl alcohol.
Patent accessed on Sept. 14, 2018