Understanding 'Maximum Oil Emulsification Percentage' in Formulations

The statement that Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer can "handle up to 20% oil" refers to the percentage of the total formulation weight, not a fixed ratio between the polymer and the oil.

1. Meaning of "20% Oil"

In cosmetic formulation, percentages are calculated based on the total weight of the finished product (% w/w).

• Example: If you are making 100g of cream, "20% oil" means the formula contains 20g of oil and 80g of other ingredients (water, polymer, actives, etc.).
• It is not a 1:20 ratio. Using 1g of polymer does not automatically mean it can emulsify 20g of oil regardless of the total batch size.

2. Recommended Usage Rate

To successfully stabilize a formula with 20% oil, you typically need to use the polymer at a concentration of 1.0–1.5% of the total formula.

• If you use only 0.1% (the minimum range), it likely won't have enough strength to hold 20% oil.
• If you use 1g of polymer in a 100g formula (1%), it can generally stabilize up to 20g (20%) of oil in a standard system.

3. Factors Affecting Stability

The "20% limit" is a general guideline. Stability can be affected by:

• Oil Type: Some oils (like heavy natural oils or certain silicones) are harder to emulsify than light esters.
• Electrolytes: Salts or acidic actives can weaken the polymer network, reducing its oil-handling capacity.
• Shear/Mixing: Proper high-shear mixing is required to create small, stable oil droplets.

If your formula requires more than 20% oil, it is recommended to add a co-emulsifier or use a dedicated O/W emulsifier system to ensure the product remains stable over time.