Improved Process Control for Personal Care Products

Introduction

Total solids measurement in personal care items such as deodorants, oral care products, and cleansers has historically been difficult to achieve using microwave-based analyzers due to the presence of non-aqueous volatile components. Because of the wide variety of volatile components present in a given sample, solids testing has historically been performed in an air or vacuum oven, which is effective at drying all sample types, but takes hours to complete. Various rapid, indirect techniques (NIR, FT-IR) have been introduced, but are limited in the types of products that can be tested and require expensive calibrations to maintain performance. Infrared moisture balances decrease test time compared to traditional oven methods, but still require up to 30 minutes to completely dry samples. Furthermore, infrared moisture balances struggle to completely dry low-solid liquids, which tend to re-condense inside the drying cavity.

The SMART 6^TM Moisture & Solids Analyzer is uniquely designed to handle the wide variety of sample types in the personal care space, whether it is water-based, contains a mixture of volatile components, or is a dry powder. The SMART 6 utilizes dual-frequency energy, specifically microwave and infrared, to rapidly analyze solids content. Low frequency microwaves penetrate the entire sample to rapidly remove volatiles through dipole rotation, while high frequency infrared energy evenly heats the surface to remove non-polar components through molecular vibration. The two energy sources work in unison, providing benefits over microwave-only and infrared-only analyzers.

This study demonstrates that the SMART 6 can rapidly analyze a wide range of personal care products for total solids with an average difference of less than 0.05% compared to reference methods.