A large private label personal care manufacturer was looking for a solution to a bottleneck in their manufacturing process for a moisturizing body wash. Body wash products can be either an oil-in-water or water-in-oil emulsion and consist of emollients and lubricants, emulsifying and thickening agents, fragrance, cleansing agents, preservatives, and nourishing agents such as vitamins.
A typical manufacturing process would be as follows:
Waxy flake/powder ingredients are melted/dispersed into an oil phase.
- The water phase is prepared separately, usually containing emulsifiers and stabilizers.
- The two phases are then mixed to form an emulsion. This is aided by heating to between 110 - 185°F (45 and 85°C) depending on ingredients.
- Vitamins are dispersed into the appropriate phase or added to the product once the emulsion has been formed.
- Mixing is continued until the end product is homogeneous.
The manufacturer produced the majority of their lotion formulas in a pair of processing vessels each measuring 8' diameter by 8' straight side (3000 USG) with shallow cone bottoms. Each vessel was equipped with a conventional 20HP, slow speed agitator drive incorporating multiple 'arms' of mixing blades and wall scraper assemblies. The wall scrapers are typically used to maintain a clean interior vessel wall for good heat transfer and to help prevent product build-up during the cooling process.
Some of the problems facing the manufacturer included:
Long Batch Times
- Extended batch times as the surface added flake ingredients tended to raft on the surface and took many hours to melt and be fully incorporated.
- Heating and cooling cycles were extended; delaying the final addition of minor formula ingredients once cooled (such as heat sensitive vitamins).
- Overall batch time took more than one shift to make, limiting production to a batch per day per tank.
Variable Product Quality
- Final product viscosities were specified as 50,000 cps, but were often found to vary significantly within the batch and from batch-to-batch.
As a result, on time and on-specification product was often lagging demand for this popular product.
Initial testing of a small sample with a Y0 Y Jet Mixer improved viscosities to 70,000 cps. Further application of shear with a Ytron Z improved viscosity further.
The customer rented a Y Jet Mixer for on site trials to manufacture a number of 50 gallon batches. The customer found that the improved mixing patterns of the Y Jet Mixer rapidly incorporated both the flake and powdered ingredients. The complete heating and cooling cycle time was reduced due to the improved mixing. Viscosities at this scale were typically double that of their existing production. The emulsion formed was more stable and was readily produced irrespective of formulation steps.
Based upon these promising results, the customer purchased (2) 20HP Y4 side entry Y Jet Mixers for the vessels described above. The existing agitator drives and paddle assemblies were completely removed.
The customer is happy to report the following positive results:
The 6 drums of wax/flake ingredients added to the oil phase took only 30 minutes to melt and be dispersed
- The heating and cooling time cycles have been reduced
- Overall batch time has been reduced from > 8 hrs to 3 to 4 hrs, permitting two batches per shift, per vessel
- Consistent viscosity and product quality throughout the batch and from batch-to-batch
- The mixers can handle formulations up to 75,000 cps.
Additionally, the mixer installation has proved to be very cost effective:
- Direct drive
- No gearboxes, no belts
- No wall scraper blades
- No internal wear components
- Much improved CIP
- No in-tank bearing/bushing.