For long-term wearable medical devices, the interaction between the adhesive and the skin is a primary concern for designers. A key factor in this interaction is breathability. An adhesive tape that allows moisture vapor to escape helps prevent the skin from becoming oversaturated, which can lead to irritation and cause the adhesive to fail. To provide reliable data on this feature, Adhesives Research uses a standardized test to quantify the breathability of its materials.
Quantifying Moisture Vapor Transmission
To quantify a material’s breathability, its Moisture Vapor Transmission Rate (MVTR) is measured. Adhesives Research utilizes the Payne Cup Method, a standardized test, to determine this value for certain skin-contact materials. This test provides engineers with a clear, quantifiable metric to compare different materials and select the one most suitable for their application.
The Test Process
The Payne Cup Method, as used by Adhesives Research, involves a standardized process to ensure consistent results.
- The test utilizes a Payne Cup, which contains 10 mL of water.
- The material sample is prepared and placed for a 24-hour dwell period.
- This entire setup is held within a controlled environmental chamber set to a temperature of 37.2°C and a relative humidity of 20%.
By measuring the change in weight over the 24-hour period, the test calculates the amount of water vapor that has passed through the adhesive tape. The final result is expressed as the Moisture Vapor Transmission Rate (MVTR) in grams per square meter per day (g/m²/day).
This standardized testing provides the reliable, fact-based data necessary for designers to make informed decisions when developing safe and effective long-term wearable devices.
