Feature 40 years of fastenings & adhesives
principle revolves around a cure inhibition system that allows a resin to harden in the absence of air. In reality, this exclusion of air is achieved by the action of bringing together the two surfaces – for instance, mating threads. The liquid hardens and fills all the inner spaces between the threads to pro- duce a solid plastic of a known strength. With anaerobics, a solution to the age-old problem of loose nuts and bolts caused by movement, shock and vibration was achieved.
Early anaerobics required the use of an accelerator to ensure their curing benefits are practical in fast- moving production situations. Today, however, those difficulties have been surmounted and versions are avail- able that are not only fast curing, but also maintain their stability for lengthy periods of time.
The anaerobic technology advanced
apace over the coming years, and now these adhesives not only lock all types of threaded fasteners, but they are also used to retain bearings, pulleys and
The last year or so has seen the launch of two new threadlocking adhesives that meet the most stringent Health and Safety requirements. Developed in Henkel’s Dublin laborato- ries, these products have qualified for a ‘white’ Material Safety Data Sheet. This means that, according to the tough EC Regulations No. 1907/2006 – ISO 11014-1, neither adhesive carries any hazard symbols, risk or safety phrases. In addition, they do not contain any declarable carcinogenic, mutagenic and reproductive toxins. Of additional benefit, these have also been granted WRAS (Water Regulations Advisory Scheme) approval, allowing them to be used with potable water.
This important breakthrough, how-
ever, has not seen any reduction in the bonding ability of the threadlockers.
Epoxies
The third area for consideration involves epoxies, and in recent years these has been innovation to improve performance characteristics. These
Loudspeaker technology may have changed over the years, but cyanoacrylate adhesives are still trusted to secure the parts
through the use of reformulation – including modification with liquid elastomers. Fortunately, this signifi- cantly improved peel strength has been achieved while retaining the typically high tensile shear strengths.
In addition, the use of specially formulated curing agents have allowed modern epoxy systems to be capable of efficient bonding at temperatures up to (and in some cases above) 260°C.
‘Adhesives have been around for a great deal longer than Design Solutions magazine – about 6000 years in fact. Nevertheless, it is fair to say that since the launch of this magazine, there have been a number of significant developments’
gears to shafts, seal pipe fittings, as well as sealing flanged surfaces by replacing cut gaskets.
Other developments over recent decades have included the ability to produce anaerobic adhesives that pro- vide torque tensioning capabilities for threadlocking functions, and the intro- duction of oil tolerant grades for thread- locking and retaining applications. The ability to ‘cure on demand’ is one reason why the automated appli- cation of anaerobics using robotic equipment has proved very popular within many industries.
include increasing the high-temperature capabilities, improving toughness and peel strength, and upgrading resistance to water, fuels, chemicals and lubricants at high temperatures.
As a consequence, epoxy adhesives are regularly to be found in industries as diverse as aerospace, automotive, marine applications, oil drilling, leisure goods, civil engineering projects, elec- tronic assemblies and medical devices. Traditionally, they have shown high-tensile shear strengths, while exhibiting low peel strength. This shortcoming has been overcome
Terex trucks
include a number of adhesive
applications that withstand the arduous conditions in which they are used
Moving on
That really is only a brief overview of adhesives over the past 40 years. Although there have been significant developments, the purpose of adhe- sives has remained the same for the best part of six millennia: the successful bonding of surfaces.
But like general technology, adhe- sive expertise will continue to develop as long as there are materials to bond, and that means innovations will continue into the future. In 40 years time, it will be interest- ing to see what has happened since this article was written. Stick around to find out!
Henkel T: 01442 278100
www.loctite.co.uk
Enter 264
S22
- 40TH ANNIVERSARY SUPPLEMENT -
Design Solutions 1971-2011
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96