Thickener Clumping in Shampoo Formulation

Question

When formulating a shampoo using water, propanediol, GuarCat, Lactic Acid, Coco-Foam-50, SulFoam, emulPearl, and an acrylate crosspolymer thickener (ThickClean™), following a process of adjusting pH early (Step 1), adding surfactants and emulPearl (Step 2), and then adding the thickener (Step 3), clumping of the thickener occurs. What is the cause of this clumping?

MySkinRecipes Expert · Accepted Answer

Troubleshooting Acrylate Crosspolymer Clumping in Shampoo

It appears you are experiencing clumping with ThickClean™ (Acrylates Copolymer) in your shampoo formulation. This is a common issue with acrylate crosspolymers and is often related to the order of addition and the pH of the mixture when the polymer is added.

Based on the properties of ThickClean™, it is designed to be dispersed in water or a surfactant mixture and then neutralized to achieve thickening. The optimal pH range for thickening is typically between 6.2 and 6.6.

Your current process involves adjusting the pH in step 1 before adding the surfactants (Coco-Foam™-50 and SulFoam™) and the ThickClean™. Adding ThickClean™ to a mixture that is not at the correct pH for its initial dispersion can cause it to clump immediately. Surfactants can also affect the hydration and dispersion of acrylate polymers.

To prevent clumping, try adjusting your process as follows:

Combine water, 1-3 Propanediol, and GuarCat™ Weight-less.
Add Coco-Foam™-50 and SulFoam™. Mix gently until homogeneous. If necessary for emulPearl™, heat the mixture and add it, then cool down if needed.
Gradually add ThickClean™ to this mixture while stirring continuously. Ensure good agitation to help the polymer disperse evenly. Avoid high shear mixing (>2500 rpm).
After the ThickClean™ is fully dispersed, slowly adjust the pH to the optimal range of 6.2-6.6 using Lactic Acid (or other suitable acid). Add the acid slowly and mix well between additions, checking the pH as you go. Ensure the acid is diluted if adding a concentrated form.

Adding the ThickClean™ before the final pH adjustment allows the polymer to hydrate and disperse correctly in the surfactant solution before it is activated and thickened by the pH change.

Other factors that can contribute to clumping include adding the polymer too quickly, insufficient mixing during addition, or adding it at an inappropriate temperature (though the description suggests preheating can help dispersion, adding to a very hot mixture might still be problematic).

By adjusting the order of addition and ensuring the pH is adjusted after the ThickClean™ is dispersed, you should be able to achieve a smooth, lump-free texture.