Understanding pH and Mixing for Your Carbon Clay Mask

Thank you for sharing your revised formula for the carbon clay mask using Rich Cream Maker. You have questions about pH and the mixing process, as well as the overall strength of the formula.

Regarding your initial question about PVP-K90, the staff is still gathering specific usage information for mask applications, so details on percentage and dry mixing suitability are not available at this time.

Let's address your questions about your revised formula:

pH Considerations

You are correct that adding acidic ingredients like Salicylic Acid will change the pH of your formula. The recommended pH for a cosmetic product refers to the final pH of the finished product, after all ingredients have been added and the formula is complete.

Both Salicylic Acid and Papaya Enzyme are sensitive to pH:

• Salicylic Acid: Works best for exfoliation at an acidic pH, typically pH 3-4.
• Papaya Enzyme (Papain): Is most stable and active in a slightly acidic to neutral range, generally pH 5.5-7.0. It also requires Disodium EDTA for stability.

This creates a conflict in your formula. To get the best exfoliating benefits from 2% Salicylic Acid, you would aim for a final pH around 3.5-4. However, this pH is too low for optimal Papaya Enzyme activity and stability. You will need to measure the pH of your final mixture and adjust it to your desired range using a pH adjuster (like Citric Acid or Sodium Hydroxide solution).

Mixing Method

Your proposed mixing method is unconventional for creating a stable emulsion mask with Rich Cream Maker. Rich Cream Maker is an emulsifier designed to combine water and oil phases. A more standard approach is:

1. Water Phase: Combine Water, Disodium EDTA, Propylene Glycol, and Methylsulfonymethane. Disperse Bentonite Clay, Activated Carbon, and RiceSorb in this phase, ensuring they are fully hydrated.
2. Salicylic Acid: Dissolve Salicylic Acid powder in a small amount of Propylene Glycol before adding it to the water phase.
3. Oil Phase: Prepare the Rich Cream Maker in a separate container. Follow the supplier's instructions regarding heating (some emulsifiers require heating, others are cold process).
4. Emulsification: If heating is required, heat both the water and oil phases to the recommended temperature. Combine the heated phases and mix thoroughly (e.g., with a stick blender) to form the emulsion. If cold process, combine at room temperature and mix.
5. Cooling: If heated, cool the emulsion while mixing gently.
6. Add Sensitive Ingredients: Below 40°C, add Papaya Enzyme. Below 60°C, add Phenoxyethanol SA. Add Vanilla Flavor.
7. pH Adjustment: Measure the final pH and adjust it to your target range.

Formula Strength

Your formula contains a potent combination of exfoliants (2% Salicylic Acid, Papaya Enzyme) and absorbents (Bentonite Clay, Activated Carbon, RiceSorb). While these are common in masks, the concentration of Salicylic Acid is the maximum allowed in leave-on products, and combined with other actives, it could be strong. It is highly recommended to perform a patch test on a small area of skin before applying the mask to your entire face to check for sensitivity.

Preservative

Yes, a preservative is necessary for any product containing water to prevent microbial growth. Your formula includes Phenoxyethanol SA, which serves this purpose, provided the final pH is within its effective range (pH 2.0-6.0).

By following a standard mixing procedure and carefully controlling the final pH, you can create a more stable and effective mask, though you will need to consider the pH limitations for Papaya Enzyme activity when prioritizing Salicylic Acid efficacy.