The technology of instant adhesives
Instant adhesives are also known as super glue or cyanoacrylates with unmatched performance and manufacturing speed. Latest technology in instant adhesives has increased its resistance to temperature by 50% to 120oC and fixture speed to just about a few seconds in most working conditions. Aside from its resistance to high temperature, instant adhesives have gained widespread popularity because of its fast drying rate and ease of adhesion on a wide range of materials. Outstanding mechanical strength can be achieved with instant adhesives with only a few drops. The use of this type of adhesive has allowed manufacturers to successfully bond different materials together so that they combine the best features in the most convenient way. However, it is important to take proper care on the application of adhesives because poor adhesion may be obtained on wet substrates.
Performance improvements on instant adhesives
Developments in cyanoacrylate technology have led to performance improvements on the adhesive. The introduction of rubber-toughened, surface-insensitive and thermally-resistant adhesives has provided many improvements over the earlier generations of adhesives. Cyanoacrylates are available in a wide range of viscosities where the application of a thin film between two surfaces can cure rapidly in order to form rigid thermoplastics with excellent adhesion to most substrates. Typically, a fixture can be achieved within 1 minute with full bond strength in 24 hours. These types of adhesives are present in most consumer stores and come in different brands. There are different types of cyanoacrylates that are used for various applications:
- Methyl cyanoacrylate – formulations based on this monomer are commercially available for metal bonding applications but they do not provide the same durability of rubber-toughened products over metallic substrates.
- Ethyl cyanoacrylate – are considered to offer superior performance in plastics and elastomeric substrates if compared with methyl cyanoacrylate.
- Low odor and low bloom cyanoacrylate – instant adhesives have the characteristic sharp, unpleasant odor if there is no adequate ventilation during application. Sometimes, the volatility of the adhesive can lead to the formation of a white haze that is called blooming. Blooming can settle around the bond line in the form of minute crystals which can be an aesthetic problem. Even if there is no performance problem with blooming, it can be minimized with adequate ventilation, removal of excess adhesive and rapid curing through the use of an accelerator.