Structural adhesives are designed to join parts without interfering with their finish or appearance. This is one thing that makes different from welding and mechanical fasteners. These adhesives are used for various assembly operations for many reasons. Unlike mechanical fasteners, they do not involve drilling holes and there is no risk of heat distortion. Also, they are capable of joining different materials without galvanic corrosion.
Structural adhesives from Adhesives Technology Corporation have the highest load-bearing capabilities compared to other kinds of adhesives. They cure in an irreversible process that helps offer great resistance to temperature and solvent. When used as bonding agents, they help get the job done quickly and easily.
Application Requirements to Consider when Choosing a Structural Adhesive
When selecting a structural adhesive, the decision must be made based on the performance and processing requirements of the application. Below are some of the application requirements that must be taken into account:
- Operational conditions. It is important to consider whether the installation temperature is hot or cold and whether the joint will be exposed to rain or saltwater or the sun.
- Resistance to chemicals. Think about the fluids and specialized chemicals that will come into contact with the joints.
- Environmental concerns. Consider if the adhesive will be used in a medical device or food packaging. Are there any regulations applicable regarding disposal and toxicity?
- Mechanical issues. Consider if the bonded part will be subject to high impact or vibrational forces.
General Properties of Structural Adhesives
Every type of adhesive can be tailored to some extent. For instance, an adhesive can be added with a thickener to increase viscosity or a diluent to reduce viscosity.
However, they can be compared according to the general properties inherent in their chemistry:
- These structural adhesives bond well to a lot of substrates and can be easily altered to achieve a range of properties. Epoxies offer high shear strength on a variety of plastics, glass, and metals. They provide high thermal, chemical resistance, minimal shrinkage, and high cohesive strength when fully cured.
- These adhesives contain similar monomers as the original anaerobic adhesives. But, they have been carefully formulated to cure even if there is air present. Usually, they bond through thin layers of oil because of their excellent solvent power.
- Cyanoacrylates. These adhesives offer good shear strength on a lot of rubbers and plastics. These rigid adhesives show low resistance to impact and peel.
- In general, these adhesives have lower strength, particularly at higher temperatures. They tend to bond well with metals, wood, and plastics.
- They typically have lower shear strength than other kinds of structural adhesives; however, have great peel and impact strength.