In recent years, adhesives have experienced a spectacular progress by replacing conventional joining techniques such as mechanical joining or welding. This progress was largely due to the important effort made in R&D to obtain adhesives on demand. The characteristics mainly assessed are its mechanical resistance, durability, resistance to high temperatures, resistance to water, electric conductivity, variable curing cycles, etc.
The largest and most important group of adhesives are structural adhesives, so named because, they do not only support the weight of adherents, but also support the mechanical stresses to which they are subject. Epoxy, acrylic and polyurethane adhesives are considered structural adhesives, as well as polyimides, silicones, acrylic foamed tapes and phenolic nitrile. Epoxy adhesives are the most rigid and have a high adherence. On the contrary, polyurethane adhesives are the most flexible and they adhere porous and irregular surfaces. Acrylic adhesives are an alternative to epoxy and polyurethane and its main advantage is that they do not require an accurate surface preparation of the adherents (as epoxy and polyurethane adhesives do).
In AIMPLAS, we are carrying out different research projects in order to improve certain properties of structural adhesives, such as mechanical properties, durability and electric conductivity properties. For that purpose, new formulations of adhesives are being developed by using fillers and nanofillers, as well as new hardeners to achieve the objectives set out. To do so, AIMPLAS’ pilot plants have at your disposal the required equipment to disperse correctly these nanofillers in the adhesive, as well as the manufacturing of specimens’ equipment together with the chemical and physical-mechanical tests needed for its verification.
Figure 1: Dispermat (with ball mill) and three-rolls calender.
Figure 2: Samples prepared to be tested and tensile test performance with unversal testing machine.
In this way, adhesives are expanding its range of applications, thanks to research and development in this field, thus making adhesive the joining method of the future.