The Expert's Corner

A global cosmetic company approached ROSS with the goal of expanding their gel manufacturing capabilities. Our team at the Ross Test & Development Center conducted a pilot demonstration to evaluate an appropriate batching and mixing procedure on a 100-gallon VersaMix Multi-Shaft Mixer.

Deionized water, phenoxyethanol, EDTA, ultraviolet absorber, colorant and other minor ingredients were first charged into the mix vessel. The mixer was closed and Carbopol powder was added through a port on the cover as the High Speed Disperser ran at 900 rpm. This speed was gradually increased to prevent powders from floating on the surface.

Once all of the thickener has been incorporated, the 9" sawtooth blade was allowed to continue running at 1,900 rpm which provided sufficient mixing action for the somewhat foamy batch with a low viscosity around 100 cP.

The dispersion stage was followed by a neutralization step with the addition of potassium hydroxide pre-dispersed in deionized water. As the material began to thicken, the Three Wing Anchor was started up and gradually increased to 80 rpm. Air was then pulled from the mixing zone until a deep vacuum of 29.8" Hg was achieved. The resulting material was a perfectly clear turquoise gel around 50,000 cP. Final batch temperature was 90°F without any external heating or cooling.

The company was extremely impressed with the results. They proceeded to install 200- and 300-gallon VersaMix Multi-Shaft Mixers at their manufacturing plants to produce various cosmetic gels and lotions.