In-mold labels use a pre-printed plastic label during the manufacturing process. The label becomes an integral part of the product after curing and serves as a decoration as well as information providing label. These labelling techniques ensure that the entire product is covered with this wrap around label for the product. Combining the decoration to the molding process cuts on the costs but can increase the manufacturing time.
This labelling method provides a complete wrap around label of the entire surface area of the container with minimal effort in full colour and various design options. Also, they are much better equipped to handle wear and tear and fading as they are a part of the container itself. They are also in most cases waterproof and made up of plastic so they can be recycled indefinitely. The only problem is that they are not available for anything other than plastic like paper, glass or metal containers.
There are mainly three types of in-mold label techniques used, they are:
- Injection molding: In this the label is printed separately and placed inside a mold. The plastic in a liquid form is then poured where it combines with the label and forms a part of the container itself. The label is on the outside of the container in this case and the can or container is usually made up of an opaque plastic material. Many of the butter tubs and ice-cream packages are done through this method,
- Blow molding: This is similar to the glass blowing process where the hot plastic is placed inside a mold and blown up to the proportions of the mold where the label is kept that fuses as one with the inside walls. The label in this case gets imprinted to the inside of the container as the product can also be seen through the packaging and label. This is used mainly for shampoo bottles, ketchup bottles, liquid soaps and detergents where a waterproof label is required.
- Thermoforming: This process does not melt the plastic but uses sheets of two plastics, one for the label and the other for the package and fuse them together with suitable heat. This sheet is now stamped into a mold and the label and plastic container sheet bind together. Ice cream cups and coffee cups are made with this process.