Achieving SPF 50 with Titanium Dioxide and Zinc Oxide

Achieving a specific Sun Protection Factor (SPF) like SPF 50 using mineral filters such as Titanium Dioxide and Zinc Oxide requires careful formulation and testing. There isn't a single fixed percentage for these ingredients that will guarantee SPF 50, as the final SPF value depends on several factors:

• Specific Product Type: Different grades and particle sizes of Titanium Dioxide and Zinc Oxide offer varying levels of UV protection and transparency. For example, some are designed for broad-spectrum UV protection, while others might be optimized for cosmetic appearance (like reducing whiteness).
• Concentration of Active Material: The percentage needed is based on the active amount of Titanium Dioxide or Zinc Oxide in the raw material, not just the total amount of a dispersion.
• Formulation: The other ingredients in the product (like dispersants, emulsifiers, film formers) significantly impact how the mineral particles are distributed and form a protective layer on the skin, which affects the SPF.
• Testing: The final SPF value must be determined through standardized in-vitro and in-vivo testing.

Generally, achieving high SPF values like 50 with mineral filters requires relatively high concentrations. Formulators often use a combination of both Zinc Oxide (which provides broad-spectrum UVA and UVB protection) and Titanium Dioxide (primarily UVB, with some UVA coverage depending on the grade) to achieve broad-spectrum protection and the desired SPF.

Based on the product information available, some types suitable for sunscreen applications include:

• Titanium Dioxide Transparent (15nm, Water-Dispersion): Contains 28% active Titanium Dioxide, with a usage rate of 1-50% depending on desired sun protection efficiency.
• Titanium Dioxide 30nm SilkTouch™: Usage rate of 5-25%, focused on UV protection.
• Zinc Oxide Transparent Dispersion (C12-15 alkyl benzoate Base): Contains 45-48% active Zinc Oxide, with a usage rate of 5-50% for desired performance.
• Zinc Oxide 40nm Dispersion (Water Base): Contains 45-48% active Zinc Oxide, with a usage rate of 5-50% for desired performance.

To formulate a product with SPF 50, you would typically start with a target concentration based on estimated efficacy data for the specific grades of Titanium Dioxide and Zinc Oxide you are using, and then perform rigorous testing to confirm the actual SPF.