There are several reasons why one would choose adhesives for industrial bonding, over other methods, such as their lightweight, resistance, and versatility. However, one of the most crucial factors to consider while choosing Adhesives is their bonding strengths. The adhesive’s capability to hold two substrates together without compromising safety is crucial for industrial applications.

Different industrial processes and equipment have different adhesive strength requirements. Hence, it is crucial to not only understand the adhesive strength required for your specific application but also select the right adhesives. To help you with this, in this blog, we will go over the types of adhesive strengths, the importance of epoxy strength in industrial bonding, and more.

A] What Is Adhesive Strength?

Adhesive strength refers to the capability of an adhesive to hold itself and the substrates together under pressure. An epoxy with weak adhesive strength might be able to hold the substrates together normally but will crack when additional pressure is applied. On the other hand, a high-strength epoxy can withstand high pressures, extreme temperatures, and all sorts of other environmental challenges.

Adhesive strength is a very important factor to be considered in industries like construction, aerospace, and automotive. As the adhesive strength defines the performance and durability of the epoxy, choosing the right adhesive is crucial for ensuring safety and reliability.

1. Adhesion

Adhesion refers to the epoxy’s tendency to hold on to a dissimilar material, in this case, the substrate. Adhesion is what keeps the non-adhesive equipment in an industry bonded with each other. As a result, it is one of the most important things to consider when selecting an epoxy.

The cause behind this attraction between two dissimilar materials can either be mechanical or chemical. The epoxy that clings to microscopic pores on the surface facilitates mechanical adhesion, which is usually the case. Conversely, chemical adhesion fuses the surface’s material and the adhesives on a molecular level.

2. Cohesion

Cohesion is more straightforward than adhesion. It refers to the tendency of a molecule to stick to itself. Cohesion is an important aspect of an industrial strength adhesive for holding itself together under pressure.

Often manufacturers put emphasis on adhesion but fail to consider cohesion strength. This leads to adhesives breaking apart while still clinging to the substrate. High cohesion adhesives are used to create structural adhesives due to their high durability. As cohesion depends on the chemical composition of the adhesive, manufacturers must select the correct epoxies for their specific applications.

B] Importance Of Adhesive Strength In Industrial Bonding

Finding an epoxy with the desired adhesive bond strength is paramount for manufacturers to first understand their epoxy needs. Usually, most manufacturers might look for the strongest adhesive for their applications. However, It is not necessary that the strongest adhesive would suit the most for your applications.

Epoxy adhesives are used for a variety of purposes, including sealing, coating, potting, and encapsulation. These applications may require different properties like thermal and electrical conductivity, chemical resistance, non-yellowing, and abrasion resistance.

The Epoxy that might provide the strongest adhesion might not offer the additional benefits necessary for the safety of the application. Certain epoxies that might be considered strong initially, may lack the temperature and abrasion resistance properties, necessary to increase longevity. The role of adhesive strength is to make sure the equipment is functioning properly without any safety concerns, and not to be strong just for the sake of it.

Considering these factors, the thing you must keep in mind while selecting an adhesive is the longevity and reliability of the epoxy. By selecting the right epoxy for your application, you can ensure that the epoxy will not deteriorate with time and keep the users safe in the long run. If you can explain your adhesive requirements in detail, experienced industrial adhesive suppliers might be able to provide you with the epoxy with the exact adhesive strength you are looking for.

C] How Adhesive Strength Is Measured?

Measuring and testing adhesive strength is paramount for quality control and adhering to industry safety and quality standards. The adhesive strength test must also be repeatable, reliable, and non-destructive to ensure the safety of the workers. There are several parameters that one should consider while testing adhesive strength.

The three most common and important methods for measuring adhesive strength include tensile strength, shear strength, and peel strength. These three tests are performed together to determine the adhesive’s mechanical strength.

1. Tensile Strength

The adhesive is applied between two substrates and then the substrates are pulled apart in opposite directions. The force is measured while pulling apart the substrates. The pressure at which the adhesive cracks is considered to be the adhesive strength’s breaking point. This amount of pressure is divided by the adhesive’s cross-sectional area to find the adhesive tensile strength. This helps to determine the stress the adhesive can withstand across the entire application area.

2. Shear Strength

The substrates attached to each other using adhesive are pulled in a sliding motion in the opposite direction. Similar to calculating tensile strength, the pressure right before the adhesive cracks is then divided by the cross-sectional area of the adhesive. The amount calculated is considered as the epoxy shear strength. Industrial professionals must consider the shear strength of an epoxy adhesive while applying it to ensure the substrate does not disassemble due to gravity or any other force.

3. Peel Strength

To determine the peel strength of an adhesive, one of the substrate’s edges must be grabbed and pulled in a peeling motion, while the other is kept stationary. The peeling motion is either elevated at 90 degrees or 180 degrees. The force is constantly applied, and the peak force that the adhesive sustains before cracking is then divided by the cross-sectional area to find the peel strength.

D] Tips For Improving Epoxy Adhesive Strength

• Thoroughly clean and sterilise the surface of the substrates.
• Increase the surface energy by making the surface rough and porous.
• The epoxy resin and the hardener should be mixed in the proper ratio to ensure efficient strength and malleability.
• The adhesive must have the desired curing properties, such as heat curing or UV curing for a reliable mechanical adhesion.
• The adhesive must also have other properties, such as chemical resistance, abrasion renaissance, and conductivity for a long-lasting bond.
• The application method of the epoxy can also affect the adhesive bond strength, so make sure to choose the correct bonding technique.
• Carefully read and follow the manufacturer’s instructions for mixing and applying the adhesive.

Conclusion

Adhesive strength is a crucial factor to consider when selecting an industrial strength epoxy. Look for adhesives that have high adhesion and cohesion strength to ensure the adhesive does not crack or deteriorate. In addition to strength, it is also advisable to ensure that the adhesive has all the necessary properties for its application in the specific industry.

If you do not find an epoxy adhesive that matches your adhesive strength and properties requirements, you can also get customised epoxy. Interested in a customised epoxy with superior strength and durability? Contact Kohesi Bond today!

Utsav Shah

Utsav Shah is a 34-year-old entrepreneur with a passion for scientific discovery. Utsav’s journey began with a deep dive into materials science, earning degrees from USC and the Institute of Chemical Technology. He’s the visionary founder of Kohesi Bond, a top-rated adhesive manufacturer, and Cenerge Engineering Solutions, a leader in heat exchangers and cryogenic pumps. With over a decade of experience, Utsav consults across various industries, ensuring they have the perfect adhesive solution for their needs. Connect with him on LinkedIn!