Labeling may seem simple, but after decades of experience, the pros at iGraphics will attest that there is more than meets the eye when it comes to adhering labels to different surfaces.
Our customers manufacture a variety of products that live in a variety of environments. So there are many factors to consider to ensure a label will adhere properly and for a long period of time. For example, surfaces may be textured, porous or coated. It all comes down to what we call “surface energy.”
Surface energy is defined as the sum of all intermolecular forces that are on the surface of a material. To put it simply, surface energy is the degree to which the adhesive and the material’s surface repel or attract. Surface tension is normally measured in energy units called dynes/cm. A dyne is the amount of force required to produce an acceleration of 1 cm/sec²on a mass of 1g. The dyne level of a material is called its surface energy. Why does this matter?
The lower the surface energy of an application material, the harder adhesion becomes, resulting in labels peeling or falling off altogether. Typical low surface materials include PVC, Acrylic, Polyethylene, Polypropylene and PTFE Fluoropolymer (Teflon®).
On the flips side, the higher the surface energy of the application material, the easier the label will stick. Typical high surface materials include Copper, Stainless Steel, Aluminum, Zinc, Tin, Glass, Nylon, Polyester (PET), ABS Plastic, and Polycarbonate. To gain the best possible adhesion, an adhesive must thoroughly “wet out” the surface to be bonded. This means the adhesive flows and covers a surface to maximize the contact area.