Reactive polyurethane adhesives have become firmly established in bookbinding because of their performance profile. The non-hazardous adhesive formulation of Henkel’s Purmelt MicroEmission product range has now been substantially improved once more through the development of Purmelt MicroEmission Cool 3400.
Significantly reduced application temperature with Purmelt ME Cool
With its low-emission hotmelt Purmelt MicroEmission Cool 3400, Henkel is offering a new product that provides another significant plus in terms of environmental efficiency and health and safety. This is the first non-hazardous PUR hotmelt that allows the application temperature to be reduced from 120 to 130 degree Celsius to below 100 degrees Celsius with no loss of performance.
The advantages of the low-temperature hotmelt are especially noticeable when one considers the ecological and economic benefits. The lower application temperature not only reduces energy consumption but also allows faster machine start-up. It puts less stress on machine components and application equipment and significantly reduces the maintenance effort for removing charred residues. All of this increases the overall service life of the production lines. Outages and set-up times can likewise be significantly decreased, with production restarting at an earlier point in the proceedings. Moreover, because the product is fast-setting, cooling sections can be shortened or even eliminated in some cases.
Higher process speeds thanks to lower temperature
The fact that Purmelt MicroEmission Cool can be processed at a lower temperature has especially positive effects on product performance. Its excellent wetting properties at lower temperatures result in extremely strong bonds. At the same time, being able to run production lines at lower temperatures automatically increases the overall process speed.
Since the heat dissipates faster, the bindings can be subjected to mechanical stresses much earlier. The special formulation of MicroEmission Cool plays a key role here. A major emphasis during product development was to achieve rapid setting after application and a fast chemical reaction. Because it can be processed at lower temperatures, MicroEmission Cool additionally shows outstandingly stable viscosity, even when applied in small amounts.
Ideal for use with all common application techniques
Purmelt MicroEmission Cool can be used for spine gluing with most conventional roller- or nozzle-type application machines for perfect binding of all common paper grades. It is also completely compatible with printing inks. As with all Purmelt products, it is exceptionally resistant to both cold and heat. The bond remains permanently elastic over a temperature range from -40 degrees Celsius to +90 degrees Celsius.
Improved health and safety thanks to reduced emissions
The use of conventional reactive polyurethane hotmelts often requires extensive protective measures because the monomeric isocyanates they contain constitute a major health hazard. By contrast, the products in Henkel’s emission-reduced adhesive range Purmelt MicroEmission contain less than 0.1 percent monomeric isocyanates and therefore do not have to be labeled with the hazard symbol Xn as conventional PUR hotmelts do.
The low processing temperature of Purmelt MicroEmission Cool reduces the vapor pressure of the monomeric isocynates to an extremely low level, which significantly reduces emissions. This practically eliminates any emissions of the already minimal content of these compounds, substantially improving health and safety levels in comparison with conventional polyurethane adhesives. At the same time, the risk of operators suffering burns during processing also decreases. As a result, the potentially health hazardous effects of reactive adhesive systems is reduced to an absolute minimum. No special safety precautions are required.