Cosmetic scientists strive to devise different ways to build unique products, and although traditional materials and processing techniques are often leveraged to provide a range of product endpoints, new combinations and emulsion starting points are gaining momentum. As technologies advance, the selection of formulating tools broadens; one popular avenue has been the development of emulsions using cold-process materials and techniques. Though this approach has many advantages over traditional emulsifiers, there are specific aspects with it the cosmetic scientist must consider.
Benefits of Cold Processing
Why the tremendous interest in cold-processable emulsifiers and blends? In the most basic sense, who wouldn’t want to finish work faster and skip unnecessary steps? Cold emulsification offers such benefits since, unlike traditional emulsification, it does not involve heating water and oil phases to temperatures as high as 80-90°C for emulsification droplet formation. Consequently, it also avoids long cooling processes, especially considering batches are typically cooled at one-third or one-half a Celsius degree per minute. This translates into substantial energy and overall cost savings for production. In turn, less energy consumption means fewer CO2 emissions, reducing the impact on the environment and aligning with the current trend for a reduced carbon footprint.
From a bench formulation standpoint, the entire process also becomes easier and more flexible. Sensitive ingredients can be combined earlier, and the initial viscosity can be met quicker, allowing more time for adjustments to be made to viscosity and color. Batches can also be split to easily post-add oils, esters, polymers and silicones to test a variety of formula variations.
Many formulation excipients and methods have been developed with the goal of processing emulsions without the use of heat, and this article will look at the classes that have evolved over the years as well as identify some of the main issues formulators face.