Practical guidelines for scaling up mineral suncare formulations

1Why scale-up needs a method

Dispersing zinc oxide is the core step of every mineral sunscreen. It directly influences performance, stability and consistency from batch to batch.

In the lab, formulators control that step with the speed of the homogenizer and the size of the beaker. In a production vessel those numbers no longer mean the same thing: the rotor is larger, the geometry is different and the batch turns over differently. Settings copied straight from the lab are a common reason why a production batch does not match the lab sample.

Each formula type adds its own demands. O/W emulsions, W/O emulsions and anhydrous sticks each need different equipment and have different critical points.

2What is inside the guide

Our technical team has put its experience with scaling up zinc oxide formulas into a practical guide for formulators and production teams. It covers:

1. 01

   Dispersing zinc oxide powder

   The step-by-step route from hot emollient and dispersing aid to a smooth dispersion, including how to add the powder without overloading the mix.

2. 02

   From lab to production

   The stages from first prototype to routine production, with the aim and expected outcome of each.

3. 03

   Scale by tip speed, not rpm

   How to translate lab homogenizer settings to production equipment, with a worked example and a practical safety margin.

4. 04

   O/W emulsions

   The vessel and homogenizer set-up this formula type needs, and what the cool-down time means for planning your equipment.

5. 05

   W/O emulsions

   Where the zinc oxide goes, and how to keep viscosity and air entrapment under control.

6. 06

   Anhydrous systems and sticks

   Keeping the solids suspended and getting the filling temperature right.

7. 07

   In-process controls

   What to check for temperature, appearance, dispersion fineness, viscosity and short-term stability, per step and product type.

8. 08

   Troubleshooting

   Likely causes and recommended actions for agglomerates, high viscosity, poor lab-to-production reproducibility, sedimentation in sticks and emulsion instability.

3The guide at a glance

The guide follows a formula from the first dispersion step to the filled product, for each of the three main formula types.

Enlarge

The picture shows the topics. The guide gives you the method:

• The order of steps for dispersing zinc oxide powder, with the temperatures and ratios we work with.
• The calculation that carries lab homogenizer settings over to production equipment, worked through from lab rotor to production rotor.
• What each formula type needs in vessels and homogenizers, so you can check your equipment before you commit to a product.
• A table of in-process controls for every step and product type, and a troubleshooting list with recommended actions.

4Get the guide

The practical guidelines are available on request. Tell us a little about your project, such as the type of formula (O/W, W/O or stick), the scale you are moving to and the equipment you will use, and we will send you the guide. We are also happy to talk it through.