Inquiry about BB Sunscreen Formulation Viscosity, SPF, and Modification
Asked by: aerie_aerie
On: November 23, 2013
Product Type:
Cosmetics
Question
I have a BB sunscreen formulation and would like to inquire about its properties and potential modifications.
The formulation includes:
- Cyclomethicone
- Dimethicone
- Silicone Gel Base
- 10% Titanium Dioxide (nano)
- 10% Zinc Oxide (nano)
- BB Micro Silk
My questions are:
- Based on these percentages, will the formulation be too thick?
- Will this formulation achieve an SPF of around 35?
- How can I modify the formula to adjust coverage and improve the texture, especially for oily skin?
Answer
Subject: Re: BB Sunscreen Formula Inquiry
Hello! Regarding your BB sunscreen formula and questions about viscosity, SPF, and modifications:
- Viscosity: Based on the percentages provided, the formula contains a significant amount of silicones (Cyclomethicone, Dimethicone, Silicone Gel Base). Silicone Gel Base itself is designed to provide thickening and a silky feel. Whether it feels "too thick" is subjective and depends on the specific grades of each ingredient used. However, the combination might result in a texture that is not overly heavy but provides some body. As mentioned in a previous reply, it might not be too thick.
- SPF: Achieving a specific SPF like 35 depends heavily on the specific grades of Titanium Dioxide and Zinc Oxide used, their particle size (nano in this case), how well they are dispersed in the formula, and the final concentration. While 10% TiO2 and 10% ZnO are substantial amounts and could potentially provide high SPF and broad-spectrum protection, it is impossible to guarantee an SPF of 35 without specific data from the ingredient suppliers for these exact grades or performing actual in-vivo SPF testing on the final product. Always refer to the manufacturer's recommended usage levels and SPF data for the specific UV filter grades you are using.
- Modifications:
- Coverage: As suggested previously, you might want to try the formula without the BB Micro Silk first. Titanium Dioxide and Zinc Oxide themselves provide significant physical coverage due to their light-scattering properties. You can add BB Micro Silk later if you need additional coverage or a specific tint.
- Texture/Feel: If you find the texture too heavy or want a lighter feel, especially for oily skin, you could consider replacing some or all of the Dimethicone with Cyclomethicone, as suggested in the replies. Cyclomethicone is more volatile and provides a lighter, less greasy feel compared to Dimethicone. You can adjust the percentages of Cyclomethicone, Dimethicone, and Silicone Gel Base to fine-tune the texture to your preference.
- Stability: Ensure all ingredients are compatible and well-dispersed, especially the nano UV filters, to maintain stability and efficacy.
It's always recommended to make a small test batch first to evaluate the texture, feel, coverage, and stability before scaling up.
Hope this helps!