Writing in its international patent, L’Oréal said the waterless formulation comprised a liquid oil-in-water carnauba wax, a silica aerogel, and a UV filter system to overcome “current drawbacks” associated with anhydrous sunscreens. The formulation could be used to make sunscreen products in various forms, including lotions, milks, creams and foams, but L’Oréal said it was preferably suited to a stick variant.
Avoiding ‘undesired changes’ in sunscreens
The company said current waterless sunscreen formulations, in any form, were susceptible to oxidation when exposed to high temperatures because of the high fatty compound content. This, in turn, resulted in unwanted sensory changes to the product, including smell and colour.
“Thus, there has been a need for an anhydrous sunscreen composition having enhanced antioxidant properties, in order to avoid undesired changes on the final product when they are exposed to high temperatures, especially on the organoleptic and visual properties of the composition,” L’Oréal wrote in its patent filing.
Carnauba wax antioxidant power
The company first tested a carnauba wax – known for its antioxidant properties and widely used in cosmetic applications – in solid form, but soon moved on to a liquid oil-in-water emulsion as the solid ingredient impacted the colour of the final formulation.
Use of liquid carnauba wax, L’Oréal said, preserved the original colour and fragrances of the sunscreen product, even when exposed to high temperatures.
Incubation tests conducted for two months showed the formula had “superior stability” when exposed to temperatures as high as 45°C, it said.
L’Oréal said the liquid wax could be incorporated at a range of 1-8% by weight of the final composition, and mixed in at temperatures between 80°C-90°C. Other fatty compounds, including waxes and oils, could also be added to the formulation.
Beauty hot on sunscreen innovation
Earlier this year, CosmeticsDesign-Europe reported on a flurry sunscreen patents filed by L’Oréal. One detailed the development of a light feel, stable high SPF variant; another covered a protecting and perfecting double-action formulation; and the other outlined a formula that simultaneously protected and whitened the skin.
Personal care major Beiersdorf also recently filed a patent on a sunscreen dispensing system that incorporated a UV exposure stamp to alert consumers when product needs to be reapplied.
WIPO International Patent No. WO/2020/154779
Published on: August 6, 2020. Filed on: January 31, 2019.
Title: “Sunscreen compositions, process of manufacturing the sunscreen composition, use of the sunscreen compositions, and use of emulsified carnauba wax”
Inventor: L’Oréal – BR. Salomao and LM. Lima