Laminating films

Laminating films made from BO-PET material

Laminating films are important materials in the packaging industry and in the processing of paper and plastic. However, other materials can also be laminated, such as wood or metal. Laminating films made from BO-PET material are characterized by their high mechanical strength and temperature resistance. Biaxially oriented polyethylene terephthalate is a polyester film that is stretched in two directions after extrusion, or oriented, as the technical term for this process is. The films owe the “BO” component in BO-PET, as well as some of the valuable properties of the material such as excellent mechanical properties, dimensional stability, clarity and temperature resistance, to this biaxial orientation.

Carrying out the lamination process

Lamination is not a clearly defined process. There are different types of lamination processes, which depend on the purpose of the lamination and the materials used. Lamination processes with BO-PET film primarily concern the lamination of paper and cardboard. Laminations can be carried out easily using commercially available devices and prefabricated laminating pouches. Such laminated working materials are particularly widespread in schools. In industrial and packaging applications, lamination is carried out on a large scale and on surfaces of completely different sizes. Different methods are used for this.

Lamination methods

Hot lamination

In hot lamination, the adhesive applied to the films melts together with the document to be laminated. With a prefabricated film pouch, the paper is placed in the pouch and heated in a laminating device. Hot rollers or two heating plates are used for this.

Cold lamination

Cold lamination uses a special adhesive that sticks at room temperature. Cold lamination can be carried out with the appropriate material without any special device.

Lamination by pressing

Lamination by pressing involves welding two films together. In this process, however, not only pressure is applied; the films are also heated at the same time and then cooled again. In this respect, the term lamination by pressing is somewhat incomplete. In the heating press, the plastic films are pressed together at high temperature. If the glass transition temperature is exceeded, the films bond together at their interfaces. When cooled under pressure in the cooling press, a stable monoblock is created.

Applications for laminating films

Laminations are mainly carried out to ensure the durability, water resistance and weather resistance of products that are used only or also outdoors. These applications are similar to those of synthetic paper. However, there are also laminations that have purely functional reasons, such as in electronics or industrial applications. Some examples of typical applications of laminating films:

• ID and identity cards
• Smart cards with RFID chip
• Maps, city maps
• Packaging
• Printed products, especially for outdoor use
• Electronic products such as displays
• Industrial applications or design applications on wood, metal or plastic

Advantages of laminating films made from BO-PET

Laminating films based on BO-PET are used for protecting and finishing printed products on paper, cardboard or plastic. They offer high tear resistance, temperature resistance and chemical and physical resistance, making laminated products durable and hard-wearing. Thanks to the clear transparency of BO-PET-based laminating films, or their matt surface, they enable razor-sharp visibility of printed information and enhance the appearance. The films protect against moisture, UV radiation and mechanical influences. BO-PET laminating films adhere very reliably and are compatible with hot and cold lamination processes. They are therefore very well suited for use in offices, schools, print shops and also for industrial applications.

Recyclability of BO-PET-based laminating films

PET materials are highly recyclable. In Germany, there is a recycling system for PET bottles that returns around 90 percent of PET bottles to material recycling. However, recyclability ends where composite materials are involved. The composites usually cannot be separated from each other, which restricts or makes material recycling impossible. Since laminated products are classic composite materials, the recyclability of laminating films is also severely limited. Recycling will only become possible once there are methods to break down laminating films, for example enzymatically, and thus recover the underlying raw materials from the collected films. Such trials are underway, but they are not yet in large-scale industrial use.

Difference between laminating films and lamination films

Laminating and lamination processes are often used to increase durability or for decorative purposes. In principle, the two processes are similar. They differ in their objectives and the materials used. The term lamination film is used when the material used for the lamination is opaque. For example, printed cardboard can be laminated on the back with another coloured cardboard to produce visually attractive packaging. Coating with metallized films is also referred to as lamination. The term laminating is used when at least one of the materials used is transparent. If, for example, a printed sheet of paper or an identity document such as an ID card is finished with a transparent plastic film to create a water-resistant and durable surface, this step is referred to as laminating, and the film used is called laminating film.

Properties of laminated documents

Documents are made water-resistant through lamination and can be washed without problems. Lamination also contributes to counterfeit protection because it is not possible to edit a sealed document. At least, this would only be possible with considerable effort. Identity documents, access passes, parking tickets, monthly transport passes or lift passes are therefore often provided in laminated form. Lamination not only fulfils a protective function, but also optimizes the functional and aesthetic appearance of the laminated products.

Broad field of application for laminations

In addition to the classic applications in the printing and packaging sector, laminating films are increasingly being used in technological fields. These include, for example, flexible displays or touchscreens. In the automotive sector as well as in the aerospace industry, components are laminated where high requirements are placed on temperature resistance and mechanical stability, while the visual appearance must not be impaired. This is made possible by the transparency of the laminating material.

Additional finishes for laminating films

Laminating films can be optimized in many different ways. Depending on requirements, additional coatings with special features can be added to the laminating film. For example, it is possible to equip laminating films with anti-reflective or anti-fog properties. Particularly scratch-resistant layers are also possible, as are improved barrier properties, for example to reduce oxygen or moisture permeability. In this way, the properties of laminating films can be adapted specifically to the product in order to meet the requirements of certain applications. Such modifications are particularly important in the food industry, because the shelf life and quality of products depend significantly on these factors.

Security features through laminating films

Special hologram or security laminates protect documents such as ID cards, bank cards or certificates against counterfeiting. These security features are difficult to imitate and therefore increase the security and integrity of sensitive documents.

Automation of work processes with laminating films

Modern laminating films can be easily integrated into automated production processes. The consistent quality of the underlying BO-PET material, its dimensional stability and mechanical strength, as well as reliable adhesion, lead to high process reliability in automated workflows. In industrial production, a stable and uninterrupted production process is of crucial importance, and modern laminating films support this through their product properties. Their field of application goes far beyond classic protective material. Today, laminating films are a highly developed material with possible applications in a wide range of economic sectors.

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