ONE-STEP LONG-LASTING COLOR/SHINE LIP GLOSS VIA LIQUID-LIQUID PHASE SEPARATION
Podium 2
Presented by: Tsang-Min Huang
One-step long-wear color liquid lipsticks are known for providing a matte finish. To provide long-lasting color performance with shine and comfort, a separate topcoat is required. However, the shiny topcoat is usually not long-lasting and required reapplying overtime. Therefore, one-step long wear and shine lipstick is a need for consumers.
To achieve one-step liquid lipstick product, scientists at L’Oreal have been exploring multiple pathways. One of the pathways is to utilize phase-separation concept. A unique and unstable formulation consisting of two partially compatible or completely incompatible phases is carefully designed and developed. The internal phase comprising pigments and liquid film formers is dispersed in a continuous phase containing high Mw and low Mw polymers. At rest, the formulation shows a phase separation, therefore it requires a mixing prior application to re-disperse the internal phase. Once the product is applied on lips, during the drying process, the dispersed phase settles down and coalesces on the lip surface to provide long-lasting color while the continuous phase spontaneously forms a thin film on the top to protect the color coat, providing shine and non-transfer. The shine of products is observed to last overtime due to the self-leveling of the polymers on the color surface.
The performance of the formulations was evaluated in-vitro through wear assays at which olive oil, artificial saliva and water resistance were evaluated by liquid contact angle measurement and by rubbing tests on thin films. The shine/gloss of products was evaluated by gloss meter. In-vivo, the formulation was tested by both expert panels and consumers for shine and wear before and after eating and drinking.
The results showed a good correlation and consistency between vitro and vivo tests. The lasting of color after eating and drinking was perceived well by consumers and the shine was observed to last at least 4 hours during daily activities.
In conclusion, the performance of our single-step long-lasting technology requires a good balance between polymer physics, phase separation kinetic and packaging design. Its excellent performance has been proved by a large-scale consumer test, showing a comparable long lasting of color to the current two-step long wear products, but exhibiting a longer lasting shine without reapplication.
To achieve one-step liquid lipstick product, scientists at L’Oreal have been exploring multiple pathways. One of the pathways is to utilize phase-separation concept. A unique and unstable formulation consisting of two partially compatible or completely incompatible phases is carefully designed and developed. The internal phase comprising pigments and liquid film formers is dispersed in a continuous phase containing high Mw and low Mw polymers. At rest, the formulation shows a phase separation, therefore it requires a mixing prior application to re-disperse the internal phase. Once the product is applied on lips, during the drying process, the dispersed phase settles down and coalesces on the lip surface to provide long-lasting color while the continuous phase spontaneously forms a thin film on the top to protect the color coat, providing shine and non-transfer. The shine of products is observed to last overtime due to the self-leveling of the polymers on the color surface.
The performance of the formulations was evaluated in-vitro through wear assays at which olive oil, artificial saliva and water resistance were evaluated by liquid contact angle measurement and by rubbing tests on thin films. The shine/gloss of products was evaluated by gloss meter. In-vivo, the formulation was tested by both expert panels and consumers for shine and wear before and after eating and drinking.
The results showed a good correlation and consistency between vitro and vivo tests. The lasting of color after eating and drinking was perceived well by consumers and the shine was observed to last at least 4 hours during daily activities.
In conclusion, the performance of our single-step long-lasting technology requires a good balance between polymer physics, phase separation kinetic and packaging design. Its excellent performance has been proved by a large-scale consumer test, showing a comparable long lasting of color to the current two-step long wear products, but exhibiting a longer lasting shine without reapplication.