New Adhesives from Henkel
Henkel Technologies, Düsseldorf, Germany, recently presented interesting new adhesive solutions for book binders and for the graphic industry.
As the latest addition to their line-up, Henkel introduced Purmelt ME 3320 from the MicroEmission series. This adhesive marks is presented as a significant improvement in the occupational health and environmental profiles of polyurethane adhesives.
Technically, polyurethane hotmelt adhesives have much to offer to many industrial processes. The only drawback is that, although they’re solvent-free, they contain monomeric isocyanates that escape during processing at elevated temperatures. If improperly used, these can damage the respiratory organs, eyes and skin, or cause allergies. For this reason, conventional polyurethane hotmelts have so far been classified as harmful to health and marked with the Xn warning symbol. Suitable staff training and the installation of fume extraction equipment are indispensable for companies processing these products.
Henkel Technologies thus set itself the goal of developing an adhesive that, while achieving the same bonding performance, emits significantly less of the odorless and colourless monomeric isocyanate vapours than conventional polyurethane hotmelts. In the course of a concerted development effort, product developers have succeeded in steadily reducing the quantity of monomeric isocyanate. This means that the existing polyurethane hotmelts from Henkel Technologies already only contain, on average, a maximum of 2% of the substance. Henkel has now achieved a breakthrough with the latest generation of polyurethane hotmelts. The quantity of isocyanate is now so low that the hazard potential during application has been largely minimised. The new MicroEmission adhesives contain less than 0.1% monomeric isocyanates and are thus well below the threshold above which labelling as a hazardous substance is statutory. As comparative measurements by several independent bodies have shown, when applied correctly, the adhesives emit up to 90% less isocyanate vapours than existing polyurethane hotmelts - without compromising on their high bonding performance.
Having successfully launched its MicroEmission hotmelts in the wood processing industry, Henkel Technologies is now bringing them onto the market as a further refinement of the Purmelt adhesives for the graphic arts industry - for use in wheel or nozzle applicators.