Oil-Based Sunscreen Formulation with Physical Filters

For customers seeking formulations with minimal chemicals, physical sunscreens like Zinc Oxide and Titanium Dioxide are excellent choices as they work by sitting on the skin's surface to block UV rays rather than being absorbed.

1. Suitability of Zinc Oxide 35nm Liquid and Titanium Dioxide 15nm Liquid (Gloss)

Yes, Zinc Oxide 35nm Liquid and Titanium Dioxide 15nm Liquid (Gloss) are suitable options for creating an oil-based sunscreen for customers who prefer minimal chemicals. Both are physical sunscreen filters.

• Zinc Oxide 35nm Liquid provides excellent protection against long-wave UVA.
• Titanium Dioxide 15nm Liquid (Gloss) protects against short-wave UVA and both short and long-wave UVB.

Using both together is recommended to achieve broad-spectrum protection covering the full range of UVA and UVB wavelengths. These specific products are liquid dispersions designed to be easily mixed into the oil or silicone phase of a formula, making them convenient for oil-based systems.

Other forms of Zinc Oxide and Titanium Dioxide exist, including powders and dispersions in different bases (like water or other oils/silicones). However, the liquid dispersions you mentioned are specifically processed for easy dispersion and are well-suited for oil/silicone systems, which aligns with your goal of an oil-based sunscreen.

2. Separation or Settling in Oil Formulas

While Zinc Oxide 35nm Liquid and Titanium Dioxide 15nm Liquid (Gloss) are specially processed for complete dispersion, they are still dispersions of solid particles in a liquid medium. In a low-viscosity oil-only formula, there is a possibility of the particles settling over time, leading to separation.

To prevent separation and ensure the sunscreen particles remain evenly distributed for consistent protection, it is crucial to increase the viscosity of the oil phase.

3. Role of Xanthan Gum and Propylene Glycol in Oil Formulas

The information you saw about using Xanthan Gum and Propylene Glycol with Zinc Oxide likely refers to stabilizing Zinc Oxide in the water phase of a water-in-oil emulsion formula.

• Xanthan Gum is a water-soluble thickener and stabilizer used in the water phase of emulsions.
• Propylene Glycol is a humectant and can help disperse ingredients in the water phase.

For a purely oil-based (anhydrous) formula or an oil/butter balm, Xanthan Gum and Propylene Glycol are generally not effective for stabilizing dispersions. To prevent settling in an oil-based system, you need to use thickeners or gelling agents that work in oil, such as:

• Waxes (e.g., Soft Wax, Polyethylene Wax) to create a more solid or semi-solid texture.
• Oil-soluble gelling agents (e.g., Hectorite Gel in a suitable oil or silicone base) to increase the viscosity of the oil phase.

Using an appropriate oil-phase thickener is essential for maintaining the stability and effectiveness of your oil-based sunscreen formulation.

4. Recommendations for Your Two Formulas

For both of your proposed formulas, Zinc Oxide 35nm Liquid and Titanium Dioxide 15nm Liquid (Gloss) are suitable choices due to their ease of mixing into oil/silicone phases and their effectiveness as broad-spectrum physical sunscreens.

• Formula 1 (Oil only): Use Zinc Oxide 35nm Liquid and Titanium Dioxide 15nm Liquid (Gloss). It is critical to incorporate an oil-soluble thickener or gelling agent (like a wax or oil-based gel) into your formula to increase viscosity and prevent the settling of the sunscreen particles.
• Formula 2 (Oil + Butter Balm): Use Zinc Oxide 35nm Liquid and Titanium Dioxide 15nm Liquid (Gloss). The butter component will naturally provide significant viscosity and structure to the balm, which will help keep the sunscreen particles well-dispersed and prevent settling.

In both formulas, ensure you mix the liquid sunscreen dispersions thoroughly into the oil/butter phase until completely uniform. Heating may be required depending on the other ingredients (like butters or waxes) to achieve a homogeneous mixture.