Silicone-Based Physical Sunscreen Formulations

Here are proposed silicone-based physical sunscreen formulations for face and body, based on your requirements.

Your understanding that physical sunscreens work by creating a barrier on the skin surface to reflect UV rays is correct. Maintaining this barrier is key to their effectiveness.

Face Formula

This formula incorporates the ingredients and percentages you specified to provide oil absorption, a soft-focus effect, and physical UV protection in a silicone base.

• Silicone Base (e.g., Cyclopentasiloxane or Dimethicone): Approximately 63%
• MatteSilica 5™ (5 Micron): 10%
  • Function: Helps absorb excess oil on the skin, provides a matte finish, and improves the texture's glide.
• Polymethylsilsesquioxane 4.5microns: 7%
  • Function: Creates a soft-focus effect to help blur the appearance of wrinkles and provides a smooth, silky feel.
• Zinc Oxide 200nm EasyDisperse™: 20%
  • Function: Provides broad-spectrum UVA/UVB protection as a physical sunscreen agent. This treated version is designed to disperse well in silicone.

Mixing Guidance: It is crucial to ensure the powders are fully and evenly dispersed in the silicone base to achieve stable texture and effective sun protection. For Zinc Oxide 200nm EasyDisperse™, pre-dispersing it in a 1:1 ratio with a silicone fluid like Cyclomethicone before adding to the main batch can help. The other powders can typically be blended into the silicone base in the final step, ensuring thorough mixing.

Body Formula

This formula focuses on providing physical UV protection with a non-sticky feel that adheres well to the skin, using a silicone base.

• Silicone Base (e.g., Cyclopentasiloxane or Dimethicone): Approximately 80%
• Zinc Oxide 200nm EasyDisperse™: 20%
  • Function: Provides broad-spectrum UVA/UVB protection. The silicone coating helps it disperse well in the silicone base and contributes to a non-sticky feel.

Mixing Guidance: Similar to the face formula, proper dispersion of Zinc Oxide 200nm EasyDisperse™ in the silicone base is essential. Pre-dispersing the Zinc Oxide in a 1:1 ratio with a silicone fluid before adding to the main silicone base is recommended for optimal results.

For both formulations, the choice of specific silicone fluid (e.g., Cyclopentasiloxane, Dimethicone of a certain viscosity) can influence the final texture and feel. Ensuring good manufacturing practices and stability testing is important for the final product.