New Nail Polish Adhesion Rig and Method

A Nail Polish Adhesion Rig and method have been developed by Stable Micro Systems to provide the solution to this assessment requirement.

During the polish drying time test, a channel 20cm long is filled with polish to a depth of 0.5 mm and wiped level using a glass rod. At this point a timer within the Exponent software test sequence is started. This channel is seated on top of the Adhesive Indexing System that has ten detents and so ten test sites are available by simply sliding the platform along. A 1 inch detented ball probe* is used for the tests, which can be turned to allow a clean test site without either replacing the probe or the requirement to clean and dry the probe between tests. This is used to perform an adhesive test at the first test site.

A specific force is held for 5 seconds to allow a bond to form. The probe is then quickly withdrawn, breaking the nail polish bonds, and the force to do this is measured. The channel is moved along to the next site and the test repeated. A set of ten tests are performed in this way with pre-set time delays between the tests. Tests are performed over the whole drying period of the polish.

The series of adhesion tests is automated by a unique test sequence developed in Exponent Connect software, with parameters such as the delay between tests, the number of repeats, applied force and holding time adjusted by the user if necessary. Additionally, an analysis macro is available to measure the above four properties across all repeats at the press of a button. With the addition of instruction messages in the sequence this provides a user-friendly solution for this type of product testing.