Hand Sanitizer Gel Problem: Cloudy and Liquid After Adding TEA

Question

I am making hand sanitizer gel and encountered an issue after mixing Carbopol and ethanol. After adding TEA at a quantity of 30ml (for a production ratio of 10,000 ml), the water suddenly became cloudy and did not turn into a gel, but remained liquid instead. What is the cause of this problem? Is there a way to fix it to make it a usable gel again?

MySkinRecipes Expert · Accepted Answer

Hand Sanitizer Gel Problem: Cloudy and Liquid After Adding TEA

It sounds like you've encountered a common issue when working with Carbopol gels and neutralizers like Triethanolamine (TEA). Here's an explanation of what likely happened and whether it can be fixed:

Cause of the Problem

Carbopol is a gelling agent that requires neutralization to thicken and form a gel. Triethanolamine (TEA) is used to raise the pH of the mixture, causing the Carbopol polymer chains to swell and create the gel structure.

However, adding too much Triethanolamine can lead to over-neutralization. When Carbopol is over-neutralized, the gel structure can break down, or the polymer may become less soluble at the very high pH. This results in the mixture becoming liquid and often cloudy, which is exactly what you observed.

Can it be Fixed?

Attempting to fix an over-neutralized Carbopol gel, especially in a large volume like 10,000 ml, is challenging and often unsuccessful.

The theoretical way to try and fix it would be to carefully lower the pH back into the optimal gelling range for Carbopol. This would involve adding a very dilute acidic solution (such as citric acid or lactic acid solution) very slowly and drop by drop while continuously mixing. The goal is to bring the pH down just enough for the Carbopol to re-gel without making it too acidic, which would also break the gel.

However, this method is difficult to control precisely in a large batch. There's a high risk of adding too much acid and making the situation worse, or simply not being able to recover the desired gel consistency and clarity.

Recommendation

The most reliable approach is to discard the current batch and start over. When preparing the new batch, add the Triethanolamine very slowly while mixing, monitoring the viscosity until the desired gel consistency is achieved. Avoid adding a large, predetermined amount all at once.

Products involved in your formulation include: