For indirect food contact and good adhesion on plastics
Nordmann is excited to be launching a new adhesion promoter: NORCOAT Bond 002. Peter Kuchenbrod, Business Manager Coatings & Inks at Nordmann, tells us more.
What is NORCOAT Bond 002 and how does it work?NORCOAT Bond 002 is a polymeric titanium phosphate
complex that reacts, for example, with OH or carboxyl groups in the substrate and directly in the coating.
How is NORCOAT Bond 002 used?
NORCOAT Bond 002 can be incorporated into formulations at 2-3% concentration, but can also be applied directly to the substrate in diluted form as a pretreatment so that it reacts only where it should act – namely at the interface point to the substrate.
Have any studies been done?
Yes, and findings have shown that the best levels of adhesion were achieved on oriented polypropylene if the substrate had also been pretreated, e.g. using corona or plasma treatment. However, good results were produced even without the substrates being primed and adhesion was shown to improve over time, reaching optimum levels after 24 hours.
How does the new product differ from silanes?
For silanes to react, they have to be activated with water. This process involves the formation of OH groups which then react with those of the substrate and the coating. NORCOAT Bond 002 reacts immediately, however.
How does the titanate interact with polyurethane (PU) systems?Dissolved one-component polyurethane systems contain a negligible level of free isocyanate, so it is possible to achieve stable incorporation without problems. In two-component polyurethane formulations, the titanate can be formulated into the curing component. It contains up to 40% alcohols, however, so if it is formulated in the isocyanate, some would certainly react and that must be taken into account in the formulation. (Incidentally,
incorporating the titanate into coatings diluted purely with ester does not produce stable results.) In both cases, polymeric phosphoric acid esters with terminal OH groups with low migration potential are formed as by-products while the film is being dried. NORCOAT Bond 002 can be used for food packaging without any problems.