Film laminating

The film lamination is usually on printed sheets, rarely on a web. The laminating film has a thickness between 12 ... 30 microns. It is processed in laminate calenders of role. The printing sheets are in this case fed to the machine in a continuous web with an overlap; after lamination they are separated by a separating device again by the film web is disconnected.

For technical reasons, a blank margin of 10 mm is applied to the sheet edges around is needed because the laminating film is somewhat narrower than the print sheet and therefore the arc in the width can not be completely laminated. Since the arc overlaps run in the machine, is also present on the anterior and posterior semicircular edge a non-laminated edge. Large technical details at the edges can be cut out of the lamination, e.g. tabs. However, it is not possible, e.g. leave out a single tab on the sheet and the space around them to hide. Most sheets are laminated, but endless sheets of paper can be concealed.

The lamination is done either as a wet lamination or thermal lamination. In wet lamination, a viscous adhesive is applied to the film, which is then applied under pressure and heat to the paper. The heat is responsible for the evaporation of the solvent in the adhesive (with dispersion adhesives, the solvent is water).

For the thermal lamination film with a thermally active adhesive precoated. This is melted by heat and connecting the action of pressure, the two materials.

Due to different surface effects, which may vary depending on the used film, lamination aims to increase advertising effectiveness. Generally, however, achieved by film lamination also protect the printed image, including against abrasion, scratch and scuff marks or dirt and moisture. Especially, protection against abrasion ensures that the beauty of the printed image remains (for example on a paperback cover) even after prolonged use and does not lose brilliance. In addition, the mechanical stability of the material is increased, which results in higher tearing and folding strength and puncture resistance.

After lamination, the color of the print image may darken slightly in their effects on the eye of the beholder. This is dependent on the printed colors.

To apply the foil lamination in the book industry, but also within range of other industries, such as the packaging sector.

Application examples within the book industry are binding brochures and protective envelopes, reference paper for book covers or folders. In addition, often postcards are laminated with glossy foil. In the field of packaging technology is being used for many products, such as folding cartons, inter alia.

For a film lamination are coated papers with basis weights between 80 ... 600 g / m2 best. And uncoated papers can be laminated, wherein the surface structure of the film emerges. This should be tested in any case before. After lamination, in paper with low grammage a curl occur. As material for the films more are contemplated. The most commonly used are polypropylene, acetate, polyester and polyethylene.

The best laminating results done by coated paper, cast-coated are optimal. Uncoated paper surfaces are indeed laminated, however, their surface structure is characterized by the lamination on the film from. This may look interesting, but also in many cases unattractive, which is why a previous test laminations is recommended in case of doubt in order to make a judgment. At too high surface roughness of the paper it can also lead to graying of the printed image, as the laminating adhesive can not fill all depressions of the surface. This may remain tiny air bubbles that prevent optimal light reflection and thus leave the printed image appear gray. If oil-based inks are used, polypropylene film can absorb oil constituents and expand thereby leading to wrinkles in the surface. Especially great is this danger in not well dried print or large solid areas, which are then laminated.

In waterless offset it can cause adhesion problems by possibly contained in the ink silicone oils, as well as in electrophotographic digital printing (print on demand), where some containing silicone fuser oils are used. In digital printing, the printing often dried by high heat from strong, which the adhesion of the film can also reduce.

Inks that are not solvent or alkali-resistant, can change during lamination especially when using dispersion adhesives. So you should check the inks on this authenticity. That is too thin (less than 80 g / m2) can be rolled with one-sided lamination; at least at its curl increases.

Costs remain a manageable framework, however, the lamination is about twice as expensive as a painting, so often the paint is preferred.

[1] Hille, Frauke Helene: Veredlungsmöglichkeiten und

Spezialeffekte für Bücher und Broschuren; Diplomarbeit, Hochschule für Technik,

Wirtschaft und Kultur Leipzig (FH), Fachbereich Medien, Studiengang

Verlagsherstellung, 2008

[2] Beckmann, Till; Morlok, Franziska: Extra:

Enzyklopädie der experimentellen Druckveredelung; Birkhäuser Verlag, 2009

[3] Webseite Achilles