The use of labels in the various technical industries places extremely high demands on their stability and durability. They are becoming more and more of a functional element in the production sequence and therefore an important component with high quality requirements. Due to its versatility, the film label is becoming increasingly established in these areas and can have considerable advantages over paper because of its specific properties. Film has a higher-quality appearance, does not wear as quickly as paper, and provides significantly more stability and resistance to the effects of the environment. It is also recyclable and can be used for transparent labels to achieve a "no label look". Comparison of the effect of water.
Whereas controversial PVC was the preferred packaging and labeling material in the 1980™s, modern industry now relies on ecologically safer materials such as polyolefin film (PE/PP) and polyester film (PET), which are the choice for a wide variety of applications. The differences between the different film types vary depending on the chemical composition.
In order to achieve the desired level of adhesive on the substrate, selecting the right adhesive is of pivotal importance. Listed here are some significant determining factors:
Special glues that bond with the surface. Extremely rough surfaces require adhesives with increased coat weight. The increased volume of glue allows it to also flow into the depths of the surface, which boosts the stability of the bond. Woelco offers special solutions no standard material can reach.
Despite the extreme stiffness of the film material it is possible to adhere the label. First and foremost, this is achieved with adhesives with high initial tack, however, the final adhesion strength has to be permanent. Another alternative is the use of overlapping labels.
Low Energy Surfaces
Some plastic surfaces have low surface tension or contain a layer of release agents. As a result, they virtually reject many types of adhesives. Special adhesives with modified resins offer numerous advantages and adhere to the surface to ultimately achieve increased bond strength.
We distinguish between:
a.) high temperatures: special adhesive does not show any visual changes under high temperatures, for instance in the production of printed circuit boards
b.) low temperatures: special freezer adhesives perform well in applications under cold conditions.
Lightly Soiled Surface
Ideally, the substrate should be completely free of dirt and moisture before any label is applied; however, as this is not always possible, careful selection of an adhesive can eliminate the need to clean dirt or moisture traces from the application surface without compromising the adhesive strength or the longevity of the bond.