TAPES + ADHESIVES All taped up


In order to safely and effectively bond substrates to ensure robust and consistent performance, it is crucial that the most suitable fastening system is selected for the application. Here 3M looks at the benefits of tape adhesives compared to traditional mechanical fasteners.


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hilst mechanical fastenings have provided satisfactory results for many decades, it is becoming apparent that there are more and more scenarios where they no longer offer the most effective solution – for example, where


speed is of the essence, appearance cannot be compromised, or the influence of the elements is greater than usual. As alternative media solutions develop and become more


easily accessible, new methods of fixing are coming to the fore. Tape adhesives in particular are seeing increased usage through their inherent performance advantages over mechanical or fusion fastening.


Mechanical fastenings vs tape adhesives Although traditionally popular, there are many downsides to


using mechanical fastenings. The application process, for example, can be highly time and labour intensive and also requires the drilling of holes which can cause leaks or weaken the substrate (although some modern products get round this). Mechanical fixings are also often visible, marring the final appearance. Mechanical fixings also do not offer anything in regard to


sealing, leaving the substrate open to the elements – water penetration, for example – if outdoors or in aggressive environments. Finally, the use of mechanical fixings creates points of stress around each fixing – the stress is not evenly spread across the surface, meaning that the failure of a single mechanical fixing can potentially be very dangerous. In contrast to mechanical fastenings, tape adhesives offer


aesthetic advantages, with cleaner lines and no protruding nails, rivets or weld marks, while their flexibility and durability frequently ensures consistent performance long after mechanical fixings start to loosen or fail. They are generally quicker and easier to apply than


mechanical fastening systems as they offer simultaneous bond and seal, aid the uniform distribution of stress throughout the cladded surface, and do not require the drilling of holes, leaving the substrate intact. Modern high strength products draw on extensive research


and development over many years to offer outstanding bonding alongside unrivalled durability and versatility. Adhesives tapes offer excellent resistance against the


elements and most importantly bond to a variety of materials, including metals, sealed wood, glass, plastics, composites, paints and powder coatings. They are conformable to allow a perfect bond line between two surfaces with no air bubbles, preventing the ingress of dirt and moisture. Furthermore, the surface preparation and product application


process could hardly be simpler. Usually, the tape is manually applied to the clean, dry substrate and pressure placed on the area with a hand roller. The liner is then removed and the second substrate added. Further pressure is then applied to the bond areas, with 50 percent bond strength achievable within 10 minutes, and full strength in 72 hours; far quicker than by using traditional methods and less affected by the elements and other external factors. Given the speed of application, costs are further minimised in this area too.


Get ahead with Snapsil


Techsil has launched Momentive’s Snapsil range - a new generation of environmentally friendly, one-component condensation cure silicones used in the assembly of electrical and electronic components and as a general adhesive sealant for metal, glass, and plastics.


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ince 2007, all materials containing >0.5 wt.% butyltin must carry a toxic label. A consultant to the European Commission (EC) has recommended banning all organotin within 3 years and the latest communications from the EC indicate that butyltin


maybe banned in some applications such as consumer DIY products. Industrial materials are not affected as yet but in the words of Momentive’s EUR regulatory team: “Organotins are an endangered dangerous species.” As a result of the movement towards more environmentally


friendly materials, Momentive have developed the Snapsil range which, in addition to being tin-free, has better performance characteristics than existing grades. Techsil’s sales director Chris Dilley comments: “I’m excited


54 Fastener + Fixing Technology • Issue 5 Apr - Jun 2012


with this launch and delighted to work with Momentive who is ahead of the regulatory game by already developing a range of new tin-free products to meet the challenges we will face in the coming years as chemical regulations inevitably tighten further.“ He adds: “Designers and engineers should take a serious


look at these grades now for products that they will be manufacturing over the next few years.” Key features of the Snapsil range include:


• Low volatility standard across all products. • Fast tack-free time (< 9 min). • Faster cure than legacy grades. • Resists stress cracking on polycarbonate, and other substrates. • Low hardness, good elongation. • Range includes flowable liquid and non-flowable pastes.


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