Adhesives have been used since 70,000 BC and their use today spans a wide range of industries from automotives to military and defence. The earliest glues were made from simple mixtures of items such as beeswax and tar as well as milk. Nowadays glue is manufactured from more sophisticated chemical mixtures. Modern adhesives require varying traits, depending on their application, and a very specific range of products is available to cater for virtually every need.
Pressure sensitive adhesion is the most widespread form - otherwise known as self-stick adhesion, which forms a bond when pressure is applied. This includes tape, labels and bookmark or note papers. Simple bonding tapes may be used for all materials, with a choice of products available to cater for different colours, thickness, adhesion strength and temperature resistance. Bonding tapes are also available for those who want a particular tape that is resistant to chemicals or ultra-violet light. Much electrical work requires specialised insulation properties that are necessary for the manufacture of components. These are designed to be far more insulating and have a higher capability to withstand the heat of an electrical current.
Masking tapes also have varying characteristics, a different colour might be needed or a gentler type of adhesive could be used when masking off delicate materials. In automotive paint work, a special grade may be required to produce very clean lines and this can be provided with premium masking papers and films.
A modern invention is the introduction of re-closable fastenings to allow multiple openings, which use a variety of technologies such as 'hook and loop' (a system similar to Velcro) or 'dual lock' (a system of interlocking mushroom shaped stems). Some of these have a very high bond (strength of adhesion) and are used in the aircraft and automotive industries.
Another form is contact adhesives, such as those used in laminate flooring where glue is applied to the two surfaces and pushed together to form a bond. Hot adhesives are yet another kind, which solidify on cooling to form a strong bond. Another class of adhesion is known as 'reactive', where two or more chemicals are mixed together and react so as to harden and form a bond. Reactive adhesion may rely on heat or moisture to form a bond also.
Adhesives are used in electronics, to attach components together and save on costs by providing instant adhesion. They are used in automotive industries for airbag assembly, in healthcare for bandages, in public or business signage, in weatherproofing of aircraft and window bonding in military vehicles.
The use of such products in various forms is widespread and they impact on many areas of our lives. As their long history continues to evolve and develop, it can be said that adhesives are sticking around in the long term.
Jeffrey Nevil writes on a number of subjects including adhesives. To read more information about adhesives see www.parafix.com
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