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Cosmetic and skincare formulations use a precise balance of ingredients to achieve the desired structure and performance of the final product. Formulators must understand the chemistry of each ingredient and how they will work together to develop products that deliver the desired performance properties like absorption, smooth application and stability, to name a few. Additionally, these products must be aesthetically pleasing and safe so consumers will buy them.
Silica Particles in Skincare and Cosmetic Formulations
Amorphous microspherical silica particles make excellent ingredients for skincare products because they improve properties like smoothness for spreadability, abrasiveness for cleansing and exfoliating, soft focus, soft scrub, matte finish, light deflection and oil absorption. They are also safe for humans and the environment.
RESIFA™ SOLESPHERE™ microspherical silica from AGC are used in skincare and cosmetics formulations to diffuse light for a matte effect, absorb sweat and sebum, and contribute to a smooth feel and application. They are environmentally friendly, effective alternatives to petrochemical-based polymeric microbeads, which are harmful to water life.
Recent SOLESPHERE Research
Researchers at AGC have long studied the performance benefits of using microspherical silica in personal care products. Recent research affirms that microspherical silica gels outperform other popular additives like plastic beads. Here’s a closer look:
Softness and Smooth Application
Softness and smoothness are achieved by reducing a formulation’s friction. AGC researchers tested samples of water-in-oil skincare formulations with the following fillers: nylon beads, PMMA beads and SOLESPHERE silica microspheres. The samples were spread on artificial leather and dried with an air drier. The texture was then evaluated using a friction tester.
Silica microspheres enhanced the formulation’s slipperiness and smoothness versus plastic beads, especially after drying.
In addition, the silica microspheres enhanced the soft-touch feel because they improve rolling and do not deform. On the other hand, plastic beads are soft, so they can deform when touched, which increases the contact and frictional force between the beads.
Oil Absorption
This study tested sebum absorption of two different water-in-oil skincare formulations – one containing SOLESPHERE silica microspheres and one without. Samples of the formulation were placed on the foreheads of human subjects. Then sebum was measured with a sebumeter at various time intervals. Results showed that the formulation containing silica microbeads improved sebum absorption.
Researchers then used artificial sebum and applied it to a plate of synthetic human skin. Sebum absorption was tested with a glossmeter to measure shine. Results demonstrated that silica microspheres performed better than plastic beads in preventing shiny spots from forming.
Matte Properties and Formulation Stability
Researchers applied a lipstick formulation sample to a plate of synthetic human skin and used a glossmeter to measure shine at three different angles. Next, they added SOLESPHERE silica microspheres to the lipstick formulation and again measured shine. The silica microspheres clearly decreased the glossiness, demonstrating that they are beneficial for providing a matte effect for cosmetic formulations.
The next study analyzed formulation stability. A lipstick formulation sample was clamped on the research platform by a supporting fixture. The sample was stored overnight at 25 °C, then measured with a rheometer to examine its breakage response to applied force. Results demonstrated that the addition of silica microspheres to the formulation sample improved physical stability.
To read or download the full silica microsphere research presentation, click here.
