Environmentally Friendly Adhesive Systems For Textile Rubber Composites
Due to regulatory requirements, formaldehyde has recently been classified as carcinogen category 1B. According to EU Commission Regulation No. 605/2014, new legal obligations apply to manufacturers, importers and downstream users. As a result of this reclassification, mixtures containing free formaldehyde levels of 0.1% or more must be labled as carcinogenic. New developments are therefore necessary to guarantee the same standard in the future. First results from Mehler Engineered Products GmbH of Fulda (Germany) show that resorcinol-formaldehyde-free adhesive systems can possibly give very good results.
Technical textiles provide solutions for a wide range of applications such as mechanical rubber goods (MRG) reinforcements and composites. The surface of reinforcing fibres and in particular the phase interface between the fiber and the rubber matrix is particularly important for such challenges and specific requirements, according to the Fulda authors in ‘Technical Textiles’ (1/2017). Resorcinol-formaldehyde latex (RFL) is the focus for textile reinforcements for use in mechanical rubber products such as tires, timing belts, hoses and air springs – especially in the automotive industry.
In order to develop environmentally friendly products, over 100 different dip formulations based on different resins and crosslinker systems were tested. The strength carriers provide the required stability, flexibility and durability to engineering end uses made from rubber. It could be seen that some of the eco-friendly immersing systems have a slightly higher static adhesion compared to the traditional RFL system. Here the static adhesion values could even be exceeded with some formulations.
Once the selected dip formulations meet the goal of dynamic adhesion and fatigue loading, they are to be offered in the aforementioned automotive applications
