Peel-Off Mask Formulation

Compatibility of Paste Maker™ (Ceteareth-25) and Polyvinylpyrrolidone K90 (PVP-K90)

Polyvinylpyrrolidone K90 (PVP-K90) is a polymer commonly used as a film-former in peel-off mask formulations. It creates the cohesive film that allows the mask to be peeled off the skin once dry.

Ceteareth-25 (Paste Maker™) is primarily used as an emulsifier to combine oil and water phases, and it also functions as a thickener and texturizer.

While these two ingredients can likely be mixed in a formulation as both are soluble in water, Ceteareth-25 is not typically the main film-forming agent in a peel-off mask. The peelable property comes from polymers like PVP. Including Ceteareth-25 might contribute to the texture and stability of the mask before drying, but its high concentration could potentially interfere with the film-forming ability of the PVP, making the dried mask less cohesive or difficult to peel.

Review of Your Proposed Formula

Your proposed formula is:

• Phenoxyethanol SA: 1 g
• 1,3-Propanediol: 10 g
• Polyvinylpyrrolidone K90 (PVP-K90): 20 g
• Paste Maker™ (Ceteareth-25): 20 g
• Glycerin (Vegetable): 10 g
• Herbal extract (Alcohol extracted): 20 ml (~20 g)
• Water: adjust to 100 g

Let's analyze the components:

• Phenoxyethanol SA: This is a broad-spectrum preservative, included at a typical usage rate (1% in a ~100g formula).
• 1,3-Propanediol and Glycerin: These are humectants that help retain moisture and improve skin feel. Their inclusion rates are within typical ranges. 1,3-Propanediol also acts as a solvent and preservative booster.
• Herbal extract (Alcohol extracted): This adds active properties. Being alcohol-extracted, it will contribute to the solvent phase.
• Water: The base solvent.

Now, let's look at the key film-forming and texturizing ingredients:

• Polyvinylpyrrolidone K90 (PVP-K90): The description states it is soluble in water up to 20%. In your formula, you have 20g of PVP-K90. The total water phase (Water + 1,3-Propanediol + Glycerin + Herbal Extract) is approximately 10g + 10g + 20g + (~19g water to reach 100g total) = ~59g. 20g of PVP-K90 in ~59g of water phase is roughly 34%, which exceeds the stated solubility limit of 20%. This high concentration may make it difficult to fully dissolve the PVP-K90, resulting in a non-homogeneous mixture and potentially poor film formation.
• Paste Maker™ (Ceteareth-25): You included 20g (20%) of this ingredient. While it can dissolve in water and act as a thickener, its primary role is emulsification, especially in oil-in-water systems. In a formula without a significant oil phase, using such a high concentration of an emulsifier is unusual and might negatively impact the drying process and the ability of the PVP film to form and peel cleanly.

Conclusion on the Formula:

Based on the properties of the ingredients, the proposed formula may face challenges in creating an effective peel-off mask. The concentration of PVP-K90 appears to exceed its solubility limit in the water phase, which could lead to dissolution issues. Furthermore, the high concentration of Ceteareth-25, an emulsifier, might interfere with the film-forming properties of the PVP.

For a successful peel-off mask, it is crucial to ensure the film-forming polymer (PVP-K90 in this case) is fully dissolved and present at a sufficient concentration to create a strong, cohesive film upon drying, without excessive amounts of ingredients that could disrupt this process.

You might consider adjusting the ratio of PVP-K90 to the water phase to ensure complete dissolution (keeping PVP-K90 at or below 20% of the water phase) and potentially reducing or omitting the Ceteareth-25 unless it serves a specific, necessary function in the formula (e.g., emulsifying a small amount of beneficial oil, though none is listed here).