Physical Sunscreen Serum Formulation (SPF 50, Lightweight, Waterproof)

Hello, I understand you want to develop a physical sunscreen serum formula with specific properties and have drafted a formula for consideration.

The formula you provided is a good starting point and has the potential to deliver the properties you are looking for.

Comments on the Formula:

• Physical Sunscreen SPF 50: The formula uses Zinc Oxide and Titanium Dioxide, which are physical sunscreens, at a combined level of 20% (10% Zinc Oxide Liquid Nano + 10% Titanium Dioxide 15nm Liquid). This level is appropriate for expecting an SPF value around 50, especially with the inclusion of PMMA Booster, which helps enhance SPF efficacy.
• Lightweight Serum Texture, Easy to Spread, Fast Absorption, Non-Greasy: The silicone group (Cyclopentasiloxane, Cyclotetrasiloxane) and lightweight emollients (LipidSoft™ C1215, Octyldodecanol, LipidSoft™ Moist), as well as the powders (PMMA Booster, BB Micro Silk™, Alumina), will contribute to a lightweight, smooth, easy-to-spread, and non-greasy texture.
• Non-Whitening: Using Nano forms of Zinc Oxide and Titanium Dioxide, along with the inclusion of Alumina, BB Micro Silk, and Beige Iron Oxides EasyMix™, will help minimize the white cast often associated with physical sunscreens.
• Waterproof: The Water-in-Oil emulsifier system (Water-in-Oil EZ™, PEG-30 Dipolyhydroxystearate, Oil-Fix™ W, SiliSolve Plus™) and the silicone components typically help the formula achieve good water resistance.
• Moisturizing, Oil Control: Butylene Glycol and LipidSoft™ Moist provide moisturizing benefits, while PMMA Booster and BB Micro Silk™ (Silica) are powders known for oil absorption/mattifying properties, helping to control shine.
• Non-Irritating or Acnegenic: Physical sunscreens are generally less irritating than some chemical filters. The other ingredients in the formula are commonly used in cosmetics. However, individual skin responses may vary, and testing on a sample group is recommended.

Notes:

• The reference formula included Tocopheryl Acetate and HDI/Trimethylol Hexyllactone Crosspolymer, while your proposed formula uses Vitamin E (dl-alpha tocopherol) and BB Micro Silk™ (Silica). These are slightly different ingredients but serve similar functions in terms of conditioning (Vitamin E) and texture modification/oil control (Silica/Crosspolymer).

Overall, this formula contains suitable ingredients and has the potential to be developed into a physical SPF 50 serum sunscreen with the properties you desire.

Mixing Instructions (for Water-in-Oil Emulsion):

This formula should be prepared as a Water-in-Oil emulsion, which involves preparing the oil/silicone phase and the water phase separately, and then slowly adding the water phase to the oil/silicone phase while using a high-speed mixer.

Phase A (Oil/Silicone Phase):

1. In a suitable container, weigh Cyclopentasiloxane, Cyclotetrasiloxane, LipidSoft™ C1215, Octyldodecanol, LipidSoft™ Moist. Mix well.
2. Gradually add Zinc Oxide Liquid Nano, Titanium Dioxide 15nm Liquid, PMMA Booster, BB Micro Silk™, Alumina, Beige Iron Oxides EasyMix™ to the silicone/oil mixture. Use a high-speed mixer (such as a Homogenizer or High Shear Mixer) to help disperse the powders and sunscreens thoroughly and ensure no clumps (this step is crucial for SPF efficacy and texture).
3. Add Water-in-Oil EZ™, PEG-30 Dipolyhydroxystearate, Oil-Fix™ W. Mix until uniform.
4. Add Vitamin E (dl-alpha tocopherol)™. Mix until incorporated.

Phase B (Water Phase):

1. In a separate container, weigh DI Water, Butylene Glycol, Magnesium Sulfate, Phenoxyethanol, SiliSolve Plus™. Mix until all water-soluble components are dissolved.

Emulsification Step:

1. Start the high-speed mixer (High Shear Mixer) in Phase A.
2. Slowly add Phase B to Phase A in a thin stream or dropwise, while the high-speed mixer is running continuously.
3. Once all of Phase B has been added, continue mixing with the high-speed mixer for approximately 5-10 minutes, or until a smooth and uniform emulsion is formed.

Final Step:

1. Switch to a slower mixer (such as a Paddle Mixer). Continue mixing while cooling the emulsion down to room temperature.
2. Check the consistency, smoothness, and color of the product.

Additional Recommendations:

• The dispersion of Zinc Oxide and Titanium Dioxide is key to a successful physical sunscreen formula. Poor dispersion will affect SPF efficacy and can result in a white cast. Ensure you use appropriate equipment for thorough dispersion at this step.
• Using a high-speed mixer during the emulsification step will help create small water droplets dispersed in the oil phase, resulting in a lightweight texture and a stable emulsion.
• This formula is a starting point. It is recommended to make small test batches first and potentially adjust the proportions of some ingredients slightly to achieve the exact desired texture and properties.
• Stability testing of the final product under various conditions is recommended. If you need to confirm the SPF value and water resistance, testing by a certified laboratory is advised.

I hope this advice is helpful!