Subject: Zinc Pyrithione Shampoo Formulation Issues

Dear Customer,

Thank you for providing detailed feedback on your Zinc Pyrithione shampoo formulation attempts and the issues you encountered. We understand the challenges you're facing with thickening, suspension, hair feel, and foam.

Based on your description and the staff's previous advice, here's an analysis of the problems and potential solutions:

1. Excessive Thickness/Clumping: Your first formula with SugarThick resulted in excessive thickness. While SugarThick is an effective thickener, achieving the desired flow and texture requires careful balancing with other ingredients. In your second formula, you switched to ClearClean, which is a good step as suggested by the staff. The thickness issue seems less pronounced in the second attempt, but the suspension problem persists.

2. Zinc Pyrithione Settling: This is a common challenge with suspending dense powders like Zinc Pyrithione. As the staff mentioned, SugarThick does not provide the necessary structure (yield stress) to keep particles suspended. While ClearClean helps with emulsification and thickening, it may also not provide sufficient yield stress on its own to prevent settling of 2% Zinc Pyrithione over time.

   • Solution: To effectively suspend Zinc Pyrithione, you typically need to incorporate a dedicated suspending agent. Ingredients like Xanthan Gum, Acrylates Copolymer, or other rheology modifiers specifically designed for suspension are recommended. These create a gel-like network that holds particles in place. You would add this suspending agent to your formula containing ClearClean. The concentration needed will depend on the specific suspending agent and the overall formula composition.

   • Mixing Tip: Ensure the Zinc Pyrithione powder is fully dispersed into a smooth slurry (perhaps with a small amount of glycerin or a surfactant) before adding it to the main shampoo base. The suspending agent should be fully hydrated and the base thickened before incorporating the dispersed Zinc Pyrithione. Gentle mixing after incorporation is needed to maintain the suspension without introducing excessive air.

3. Hair Tangling and Stiffness: As pointed out by the staff, Lauryl Glucoside can contribute to a feeling of stiffness or friction on hair, especially when used at certain pH levels or concentrations, or without sufficient conditioning agents. While you included CTAC (Cetrimonium Chloride) at 1% in your second formula, which is a cationic ingredient intended to reduce tangling and improve feel, the overall surfactant system might still be too stripping or the conditioning effect is not sufficient.

   • Solution: Follow the staff's suggestion to replace or reduce the amount of Lauryl Glucoside. Consider using alternative or co-surfactants that are known to provide a better feel on hair. Ensure your cationic conditioning agent (CTAC or GuarCat) is compatible with the surfactant system and is included at an effective level. You might also consider adding a small amount of a conditioning polymer or silicone derivative suitable for shampoos if further improvement is needed, ensuring compatibility with the rest of the formula, especially the suspending system and clarity if desired.

4. Low and Unstable Foam: This issue is also likely related to the surfactant blend, particularly the presence of Lauryl Glucoside, as noted by the staff.

   • Solution: Replacing or reducing Lauryl Glucoside with surfactants known for better foam performance can help. The ratio of your primary surfactant (Coco Betaine) to secondary surfactants is important. You could explore adding a surfactant known for boosting and stabilizing foam.

Summary of Recommendations:

• For Suspension: Add a dedicated suspending agent (e.g., Xanthan Gum, Acrylates Copolymer) to your ClearClean-based formula to keep Zinc Pyrithione dispersed. Optimize the mixing procedure for Zinc Pyrithione.
• For Feel and Foam: Replace or reduce Lauryl Glucoside. Adjust the surfactant blend to include alternatives or co-surfactants that offer better foam and a smoother feel on hair. Ensure your cationic conditioning agent is effective.

We understand the staff is forwarding this to the lab for testing, which is the best approach to fine-tune the formula and mixing process for optimal results. The lab will be able to test specific ingredient combinations and procedures to address the settling and performance issues.

We hope this explanation helps clarify the potential causes of the issues and provides direction for further development.

Sincerely,
[Your Name/AI]