Security ranks first: heat lamination of card films

Paul Boughton
Christina Barg-Becker looks at the advantages and uses of modern bonding technology.

Today bonding technology has found its way into almost every industry. Not least because of benefits such as flexibility, versatility and optimal handling, the use of double-sided adhesive tapes is an adequate fastening method.

But sometimes in certain industries, such as the manufacturing of security documents, demands are made which can neither be fulfilled by an adhesive tape nor by a liquid glue.

Here, reactive coatings are the answer. With the new product range DuploCOLL TS (Thermo Setting) from Lohmann, the secure lamination of films, eg in cards or passports, is possible.

Method: heat lamination

When manufacturing security documents, for example, identity cards or passports, security ranks first. In other words, the printed or decorated card films which are used here must be connected to one another in a fraud resistant way. Heat lamination is the suitable process for ensuring this. Here, the heating of the coated film leads to a cross-linking of the adhesive that has been applied beforehand. After this reaction, the adhesive builds up an irreversible connection with the film and the next card layer.

Furthermore, this process is suitable for joining materials with different physical and mechanical properties. By doing so, a sturdy surface is produced and the laminated document becomes resistant against external impacts, such as, for example, water.

Moreover, a belated treatment of the welded documents by separating the layers - eg with solvents - is not possible.

Finally the protection against forgery is increased. For many years Lohmann's Product Management has successfully dealt with speciality coatings, notably in the field of security documents. Today, this is apparent in the new product range Duplocoll TS. This product range of heat activated speciality coatings is easy to handle, suitable for heat lamination and achieves a performance comparable to liquid glues. Concerning the application on commercial laminators DuploCOLL TS demonstrates exceptional adhesive qualities on all customary card materials such as PVC, PC and PETG.

Heat activating speciality coatings

Reactive adhesive systems on various chemical bases - from polyamide, polyester, polyurethane to epoxy resin - form the basis of these speciality coatings. They are used on normally laser-inscribable, coated polycarbonate films and transfer systems (pure heat-sealed films).

Because of this broad adhesive basis DuploCOLL TS is suitable for a multitude of applications, such as, for example, the bonding of RFID-inlays, lamination of core films or bonding of overlay films on commercial printing inks. Furthermore the broad temperature spectrum, which is a special feature of this industry, is no problem for these special coatings. For the process of heat-lamination temperatures between 120°C and 190°C (248°F - 374°F) are typically. No problem for DuploCOLL TS and actually one of these reactive coatings shows its high performance at 80°C (176°F) already. As well as the creation of a secure connection, further features of the new product range are: protection against forgery, transparency, protection of printing inks, hydrolysis stability, minimal distortion and consistency against dynamic loads (eg bending forces). And as levelling course between brittle plastic layers, these coatings avoid tension cracks.

All in all, the broad product range Duplocoll TS of coated overlay films and transfer systems is a reliable coating technology and offers key benefits to the manufacturers of security documents. Because of their longevity and resilience even final consumers benefit from it.

Enter X www.engineerlive.com/ede

Christina Barg-Becker is with Lohmann GmbH & Co.KG, Neuwied, Germany. www.lohmann-tapes.com

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