Automated Viscosity Measurement of Raw Materials for Cosmetic Products

Introduction

For producers of oil-based cosmetic products, viscosity is an essential parameter to be determined. As many pure oils used as raw materials show a freezing point close to ambient conditions, their viscosity strongly influences storage, transportation, and processing conditions. Moreover, finished retail products, such as creams or balsam oils, require a convenient application by customers at any time.

Automation of viscosity measurements provides several benefits over conventional manual measurements due to reduced handling errors, higher reproducibility, reduced costs per sample, and increased productivity due to the option to work in a 24/7 mode.

This report presents test methods for viscosity measurements of coconut oil, palm oil, and shea butter as well as oil-based finished products using the SVM 3001 in combination with the sample changer Xsample 631.

Instrument set-up

For the test of oil samples, the SVM 3001 is used. It features a viscosity measuring cell and a density measuring cell which are both filled in one go. The instrument’s internal software provides several measurement methods including single point and repeated measurements in four different precision classes from “Ultraprecise” to “Ultrafast”, while each class corresponds to defined stability criteria for temperature, viscosity, and density.

For repeated measurements, the software features default deviation criteria for repeatability depending on the selected precision class:

• For viscosity from 0.1 to 2.5%
• For density from 0.0002 to 0.0010 g/cm³

The Xsample 631 is an integrated filling unit that provides sample preheating, fully automated filling of the master instrument’s cells as well as cleaning with up to three rinsing liquids. Depending on the sample, different filling and cleaning modes can be selected to offer optimal procedures for different samples.