Water Drop Absorption
Water Drop Absorption is a test designed for measuring the degree of sizing of corrugating medium or other relatively unsized (water leaf) container board. It is not appropriate for more heavily sized papers or boards. Virgin corrugating mediums have been shown to self-size over time, and accelerated aging tests are often employed to predict the amount of self-sizing with time (TAPPI T835, appendix A). In this test a 50 µl drop of water is applied to the surface of the sample and the time for complete absorption of the drop is recorded. The degree of water absorption by a corrugating medium influences its performance during the corrugating process and affects the strength properties of the converted product.