Waterproof Body Sunscreen with UVA1 Protection
Question
I am looking for a recipe or guidance on how to make a waterproof body sunscreen (500ml) that provides UVA1 protection. The staff suggested looking at the recipe section and using Water-Capsule for waterproofing. Could you provide a formulation approach or ingredient suggestions for achieving this, specifically incorporating UVA1 filters like DHHB?
Answer
Waterproof Body Sunscreen with UVA1 Protection
Creating a stable and effective waterproof sunscreen formula requires careful consideration of ingredients and mixing techniques. While providing a complete, ready-to-use 500ml formula is complex and requires specific testing, I can guide you on key ingredients based on your needs for waterproofing, UVA1 protection, and ease of mixing, referencing the previous staff suggestion.
Key Ingredients
Water-Capsule™ (Water-in-Oil Cream): As suggested by the staff, this is an excellent emulsifier for creating water-in-oil emulsions. This type of emulsion is ideal for waterproof products because the oil phase forms the outer layer, repelling water. Water-Capsule™ is special because it allows you to create a water-in-oil cream with a lower oil content (5-20%), resulting in a less sticky feel compared to traditional water-in-oil formulas. It also helps disperse pigments and sunscreens evenly.
DHHB (Diethylamino Hydroxybenzoyl Hexyl Benzoate): This is a highly effective organic UVA filter that provides strong protection in the UVA1 range (320-390 nm). It is known for its stability under sunlight and can be used with other sunscreens, including physical filters like Zinc Oxide. To achieve high UVA protection (e.g., PA++++), a concentration of >7.5% DHHB is typically needed. DHHB is a powder and needs to be dissolved in the oil phase, usually with gentle heat (around 80°C).
Formulation Considerations
A waterproof sunscreen using Water-Capsule™ would involve creating two phases:
- Oil Phase: Contains oil-soluble ingredients, including Water-Capsule™, DHHB (dissolved with heat), other oil-soluble sunscreens (for UVB and potentially additional UVA protection), and any other oil-soluble additives.
- Water Phase: Contains water and water-soluble ingredients.
The oil phase is then added to the water phase and blended to form the water-in-oil emulsion. The mixing instructions for Water-Capsule™ provide detailed steps for this process.
For a body sunscreen, using DHHB in combination with Zinc Oxide can be a cost-effective way to achieve broad-spectrum and high UVA protection, as Zinc Oxide also provides UVA protection.
Important Note
Developing a stable sunscreen formula with specific SPF and PA values requires careful formulation, compatibility testing of all ingredients, and laboratory testing to confirm the final SPF and PA ratings. The example formulas provided in the Water-Capsule™ description can serve as a starting point, but adjustments will be needed to incorporate specific UV filters like DHHB and achieve desired protection levels and texture for a 500ml batch.
While Water-Capsule™ makes the emulsification process easier (often no heat needed for emulsification itself, though DHHB requires heat for dissolving), formulating a stable sunscreen still requires attention to detail regarding ingredient compatibility and mixing procedures.
