Wicking - What is wicking?
A property of materials defined as the tendency of a liquid to travel through the material regardless of (and sometimes in opposition to) external forces such as gravity. Also known as capillary action or capillary motion, wicking occurs due to intermolecular forces (or adhesion) between the liquid and the solid surface that surrounds it and the cohesion of the liquid itself, and results in the absorption of the liquid into the material. For example, if the attraction between the surface particles of a liquid and the surface particles of a sheet of paper (and the internal cohesion of the liquid) is great enough, the liquid will be drawn up into the paper, even if the sheet is being held above the liquid. Wicking often occurs in porous materials, such as paper.
In labelling, the absorption of liquids can be both desirable and undesirable. For example, paper used to make labels usually requires some moisture content to produce quality print results and, when using some printing inks, it is vital that the face material is able to absorb the ink to ensure that the print stays in place. However, wicking can also be an undesirable occurrence that results in a face material becoming unstable (because it contains too much moisture) and/or being discoloured by the liquid, or can cause issues with print quality (because the ink has spread throughout the face material).Go Back to Glossary