In-mold labeling (IML) is a product decoration method that has grown in popularity over the past 10 to 20 years. Why? Because it can provide lots of apple-pie type of stuff—improved quality and shelf appeal, reduced waste, reduced cost, and better durability. Who can argue with that?
The IML process gets its name from how the label is applied to the plastic packaging container. The label is placed “in the mold” as the container itself is being formed.
Plastic containers are produced using several different forming methods, including thermoforming, injection molding, and blow molding. To a large degree, the forming method used is dictated by the shape of the container.
IML is used in both injection molding and blow molding forming methods. In injection molding, molten plastic material is injected, under pressure, into a cavity (mold) that forms the shape of the container. For IML, a label is properly positioned in the cavity prior to the injection of the plastic. After the material is injected into the mold, it is allowed to cool, with the label becoming an integral part of the container.
Blow molding is similar to blowing up a balloon. The heated plastic material is extruded in the form of a tube. A mold is clamped around this tube and air is blown into the plastic tube to force it out against the cavity walls to take the shape of the bottle or container. With IML, the label is again, properly positioned against the cavity wall and adheres to the formed container as it cools to its final dimensional shape.
Since the labels become an integral part of the container, Shelley Cooper, product sales manager for Valéron® Strength Films, an ITW Company, says, “IML offers more durability, with a longer lasting and better looking appearance. IML labels are basically melted to the carrier and become one unit.”