In-mold label is the use of paper or plastic labels during the manufacture of containers with an IML injection machine, in-mold labeling or IML inflatable plastic machine or thermoforming processes. The labels act as an integral part of the finished product, which is then delivered as a pre-decorated item. Combining the decoration process with the molding process reduces the total cost, but can increase the manufacturing time. This technology was first developed by Owens-Illinois in collaboration with Procter & Gamble to offer pre-labeled bottles that could be filled on a product filling line. This process was first applied to Head & Shoulders shampoo bottles.
How the IML injection machine works
In-mold labeling (IML) was originally designed for blow molding machines, although advances using injection molding or thermoforming with fed systems have increased the efficiency of the labeling process. The basic concept involves coating the back of the label with a thermal layer, followed by a substrate material onto which heat-resistant ink is applied. Then a heat-resistant coating of varnish is applied. This process eliminates the need to heat treat bottles prior to labeling in order to achieve adequate adhesion. Initially, paper was used as a label substrate on which heat-reactive adhesive was applied. In recent times, polyolefin substrates such as polyart from Arjobex synthetic papers have been used. which creates the advantage that the waste of polyethylene and polypropylene bottles produced in the molding process can be recycled without the need to remove the label before recycling.
In-mold labeling injection machine
There are different techniques for doing the labeling process in the mold. Vacuum and compressed air can be used to control the labels, static electricity can also be used. Electrostatic charging electrodes charge a label during transfer to the IML injection device so that when the label is placed on the tool and released by the labeling robot, it wraps itself onto the tool. Most label placement robot systems are not required for specific plastic injection machines and can be used with modern presses.
Labels may be paper or a material similar to the molded product. Polypropylene or polystyrene is usually used as the label material, and its thickness is between 15 and 40 micrometers. In some Asian countries such as (Taiwan), (Laos), (Cambodia), (Myanmar) and (Thailand), IML is called differently than in the West. In the large plastic industry group GIFFINDEX (Thailand), IML with a size of 20 microns has been called (Foil In Mold) since 1998, which has caused most Asian business operators to call it (Foil In Mold). (label) or (film), so IML industry operators in the region should learn more about other names. Perforated label materials are also used. It is a sandwich material that has a spongy layer sandwiched between two very thin solid layers. The advantage of perforated film is better adaptation to small radius curves on a product. Multi-layer film can be used to decorate products, which provides high wear resistance. This type of film has a printed surface that is protected by a second film layer with a thickness of 30 or 40 micrometers. Products that use this type of label may include household containers, food industry packaging containers, or car interior components.
In-mold labeling is a popular method for decorating injection molded parts for consumer electronics and plastic bottle caps. Manufacturers of notebook computers and mobile phones use IML technology to resist more wear and tear than spray painting or pad printing. IML can provide more decorative options than other methods. Multi-color printed graphics and offset lithography printing are used to produce products with higher quality graphics than other decoration methods. Most applications in this field use second-level graphics. Embellishments are printed on the back of a transparent substrate, usually polycarbonate or acrylic, 0.125 to 0.375 mm (0.005 to 0.015 in) thick. The injection molded plastic is on the ink side of the film. These labels are sandwiched between the film layer and the injected plastic, resulting in a label that does not rub off during use. Electrical systems can check the exact position of the label and can confirm the authenticity of the label.
In-format labeling isn’t just about creating better packaging for consumer brands. The benefits start during the manufacturing process, continue through the customer experience, and end with more efficient recycling.
In-mold labeling is a process in which a product label is automatically placed directly into the cavity of the mold and held in place by static electricity. The mold is then closed and the plastic is injected onto the label, creating a fully integrated functional label in one production step. No additional decoration is required.
Advantages of the IML injection machine
1) Versatility of shape
The process of labeling in the mold can accommodate various packaging shapes such as round, oval, square and rectangular, as well as package lids with integrated and fixed cover.
2) Advanced aesthetics
In-format labeling enables a wide variety of textures, colors, finishes (including metals), and high-resolution images. This creates a richer, more vibrant look than can be achieved with traditional sticky paper and plastic labels.
3) Very practical
In-format labeling supports features that improve brand look and feel, including:
Double sided printing
Protection against oxygen and UV
The resistance of the labels
Invisible UPC Codes (Digital Watermark)
In-mold labeling parts have high wear and scratch resistance compared to traditional decoration methods or adhesive labels. Labeling is heat-resistant, moisture-resistant and temperature-stable, ideal for microwave, frozen and refrigerated products.
For example, in-mold labeling won’t tear, peel, or wrinkle, even when wet, because the label is injected into the plastic.
The final product is fully recyclable because the label and the product are one material. They do not need to be separated before entering the recycling stream, making the recycling process more efficient.
Also, since the labeling inside the mold is done automatically and is completed in one step, the production process is shorter and eliminates the need to carry and store empty packaging. All contribute to an environmentally friendly production process.
Purchase of IML injection molding machine
To buy all kinds of plastic injection devices and inflatable plastic with labeling feature in IML format, please contact our experts through communication channels.
Pars Machinery Company provides the most up-to-date plastic injection and pneumatic injection machines with automatic labeling option