Conventional reactive PUR hot melts that have been used successfully in many different industries and applications for decades contain monomeric diisocyanate, which is necessary for the chemical crosslinking reaction and largely influences the excellent bonding characteristics of those adhesives. However, the diisocyanates can lead to the formation of monomeric fumes of acute toxicity when the adhesive is melted. Appropriate precautionary measures are therefore necessary to protect the employees working in production. For instance by installing ventilation and extraction systems or by wearing appropriate protective equipment. Depending on the concentration, diisocyanates have an irritating effect on the skin, mucous membranes, eyes and respiratory tract. In addition, they may cause allergies.
On the initiative of the German Federal Institute for Occupational Safety and Health (BAuA), the EU regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) has been developing ideas since 2012 on how quality standards and occupational safety can best be balanced in future to improve the level of health and safety at work. Based on the latest decision, the commercial processing of products containing diisocyanate will still be possible in the future. The condition for that is that the processor and user receive a regular training and qualification on the safe handling of products containing diisocyanates.
Standard PUR hot melt adhesives generally have a residual monomeric content of approx. two percent by weight and are therefore declared hazardous materials and labelled with the GHS pictogram “Health hazard”. According to the currently applicable GHS requirements, products with a free monomeric diisocyanate content of no more than 0.1 percent by weight can have a hazard-free labelling.
Jowat has been supplying an extensive portfolio of monomer-reduced PUR hot melt adhesives not subject to hazard labelling for many years already. Adhesives from the Jowatherm-Reaktant® MR product line are already established in a wide range of applications, for instance in the furniture, automotive and textile industries as well as in bookbinding. They provide a broad spectrum of benefits: They are demanded for hazardous-substance-free production areas where conventional PUR adhesives cannot be processed. In other cases, they are specifically required by customers who are concerned about the use of hazardous substances in the manufacturing of their products. The training necessary for processing and the costs in time and money involved are avoided. A major reason to change to modern adhesives of course also lies in the protection of employees. In addition, the modern PUR MR hot melt adhesives from Jowat often also deliver a superior performance compared to the conventional alternatives.
In January 2020, Jowat launched Jowatherm-Reaktant® MR 604.90, the world’s first PUR hot melt adhesive with hazard-free labelling that is certified according to RAL-GZ 716 for window profile wrapping, thereby facilitating a production free of hazardous materials and without limitations in the window industry. In addition, the patented adhesive manufactured in Detmold has impressive performance characteristics: “Monomer-reduced does not equate reduced performance,” emphasises Maik Johanntoberens, Product Manager at Jowat. “Our new adhesive impresses with outstanding resistance to hydrolysis and high initial strength especially on profiles with sharp edges. Coupled with a suitable NEP-free and VOC-reduced primers from our portfolio, it can be used to bond over 95 % of PVC- and PMMA-based decor foils established on the market. The RAL-GZ 716 requirements are easily met. High peel strengths or foil tearing can be expected 24 hours after laminating already in roll peel tests according to DIN 1372.”
Convenient for all who want a healthier production: Changing from a classic PUR hot melt to a new PUR MR hot melt adhesive is generally uncomplicated and several customers have already successfully made the change. The new Jowatherm-Reaktant® MR 604.90 can be applied using all established wrapping units with the usual processing parameters. It is compatible with a wide range of feed speeds from 6 m/min. up to 40 m/min. and provides maximum flexibility for processors.
Maik Johanntoberens is proud of the new monomer-reduced product range from Jowat: “Our high-performance products with hazard-free labelling provide future-oriented technical solutions for the bonding processes of our customers, which take into consideration the constantly growing ecological and economic requirements and promote healthy manufacturing environments.”
The article is published in the magazine ''Bauelemente Bau 09/20" in German language(www.bauelemente-bau.eu). You can download the original article down below.