Sunscreen Formula Separation Issue

The separation observed in your silicone-based sunscreen formula after 7-10 days is likely due to the instability of the dispersion of the solid particles (Titanium Dioxide, Zinc Oxide, and BB Micro Silk) within the high concentration of silicone oils (Silicone base, Cyclomethicone, Dimethicone). Over time, the solid particles settle out, causing the clear liquid silicone phase to separate.

To prevent this separation and stabilize the formula, you need to incorporate an ingredient that helps to keep the solid particles evenly dispersed in the silicone base. As suggested, adding an emulsifier or dispersant suitable for silicone systems is the correct approach.

We recommend adding SiliSolve™ at a concentration of 1% to your formula. SiliSolve™ acts as a binder that helps to stabilize the dispersion of powders and other ingredients in the silicone base, preventing settling and separation over time.

How to incorporate SiliSolve™:
Mix SiliSolve™ into the silicone phase (Silicone base, Cyclomethicone, Dimethicone) until homogeneous before adding the solid ingredients (Titanium Dioxide, Zinc Oxide, BB Micro Silk) and mixing thoroughly to ensure a stable dispersion.

By adding SiliSolve™, your silicone-based sunscreen should maintain a stable, homogeneous texture over time.