Adhesives, with their versatile applications in our homes, cars, workplaces, and even nature, have always piqued our curiosity since childhood.
But not all adhesives are built the same. Some are meant to peel off easily, while others need to hold something as critical as an aircraft wing under extreme conditions. And yet, the underlying question remains what makes adhesives stick?
At their core, what makes adhesives work comes down to two things: adhesion (how well they stick to a surface) and cohesion (how well they hold themselves together). Every adhesive manufacturer, including those making polyurethane industrial adhesives, relies on these forces when designing their products.
Let’s take a closer look at how industrial adhesives differ from everyday glue and why they stick so well.
Basic Science behind sticking
Irrespective of the chemical adhesive type, sticking depends on two key concepts: cohesion and adhesion.
Adhesion – Gripping the surface
Adhesion is when substances bind to each other. This happens when an adhesive can latch onto a surface by seeping into it, bonding with it, or attracting it at the molecular level.
1. Mechanical Adhesion
The adhesive flows into microscopic pores, cracks, or irregular areas on the surface. Once it hardens, it forms a strong mechanical interlock and grips the surface physically.
2. Chemical Adhesion
The adhesive reacts chemically with the surface to form bonds. This can include
- Covalent bonds
- Ionic bonds
- Van der Waals forces
Besides this, some adhesives also use electrostatic charges to attract the surface (for high-tech/sensitive applications).
Cohesion – the right amount of hold
Cohesion is the force that holds the adhesive together. It makes molecules grip each other inside the adhesive, giving it body, structure, and resistance to breaking.
Besides these two forces, high-performance and pressure-sensitive adhesives involve two more critical mechanisms: curing and tack.
Curing Mechanisms
Curing is the process that makes an adhesive harden and reach its full strength. This can involve evaporation of solvents, chemical reactions initiated by heat or light, or simple drying processes.
Common types of curing
- Heat curing: needs a high temperature
- UV curing: hardens when exposed to light
- Air drying: solvent or water evaporates
- Moisture curing: reacts with moisture in the air
Tack: Tack is the stickiness you feel when an adhesive touches a surface lightly. It comes from the surface stickiness of the glue before it fully cures. A high tack doesn’t mean the bond is strong; it starts quickly.
The difference between the sticking of everyday glue and industrial adhesives comes down to these key points only (adhesion, cohesion, curing, and tack). Every day, glue forms a weak physical bond, while industrial adhesives create strong chemical bonds and mechanical interlocks.
Adhesive manufacturers in India and worldwide design custom formulations based on these key sticking principles to meet industry requirements.
Common Types of Adhesives and the Science behind them
1. Acrylic Adhesives & MMAs (Methyl Methacrylate Adhesives)
They work by linking small molecules called monomers into long chains called polymers. MMAs are a fast version of acrylics that make tough bonds, especially for metals and plastics.
2. Epoxy Adhesives
Epoxy comes in two parts (resin and hardener) that you mix. When mixed, they react and form a tough, complex network of molecules.
3. A high-temperature pressure-sensitive adhesive (PSA)
High-temperature pressure-sensitive adhesive manufacturers make innovative adhesives designed to stick firmly under pressure and withstand high heat, often up to 200°C or more.
4. Elastic Adhesives & Sealants
These adhesives stay stretchy after they dry. Their molecules don’t lock tightly, so the glue can bend and move without breaking.
- Contact Glues: When applied on both surfaces and dried, the glue sticks immediately and firmly.
- Vulcanising Glues: This glue reacts with rubber parts to form strong, stretchy bonds by linking rubber molecules.
Innovation in high-performance adhesives
Adhesive technology is expected to evolve further to meet more challenging industry demands. New formulas are expected to be developed to cure faster yet create super-strong bonds. Innovations have also let adhesives withstand higher temperatures and harsher chemicals without breaking down.
Industrial adhesive companies now tailor products for specific applications, improving performance and cutting costs. Moreover, as industries demand stronger, faster, and greener solutions, industrial adhesive manufacturers continue to innovate to meet these needs.
Conclusion
High-performance adhesives stick because of advanced chemistry and material science. They form strong, lasting bonds that keep everything together, even under tough conditions.
Need high-performance adhesives that truly stick? Connect with Jesons for custom formulations that meet your industry’s demands.
FAQs
Can adhesives replace traditional fasteners like screws and bolts?
What industries rely most on high-performance adhesives?
Construction, automotive, aerospace, electronics, medical, packaging, and renewable energy.
What makes pressure-sensitive adhesives stick without curing?
Pressure-sensitive adhesives rely on van der Waals forces and surface tack. These adhesives remain sticky and bond instantly with light pressure.
