Different Adhesive Types & How to Use

There are many different types of adhesives, each for specific conditions & applications, and there are multiple factors to consider when choosing the correct product. Adhesives can be categorized in different ways, according to their chemical composition, physical form, classification or load bearing capability.

In this article, we will discuss different adhesive categories and how to use each of them.

ADHESIVES BY CHEMICAL COMPOSITION

Different adhesives can be categorized by their chemistries. Below are a few examples of available chemical compositions.

Epoxy adhesives
Epoxies are a type of structural adhesive. They are highly temperature and solvent resistant and can be structurally bonded to most types of materials, such as metals, ceramics, wood and plastics.

Polyurethane adhesives
Polyurethanes are polymer-based adhesives used for constructions requiring high strength bonding and permanent elasticity. They are often offered as two-part adhesives and have many uses. Unlike epoxy adhesives, they require moisture to set, which means they can be used for projects where other types of glues are often unsuitable.

Polyurethane adhesives, such as the Adbond EX 5690, can be painted for an ideal finish, offer high flexibility and can be used in any weather. This makes polyurethanes ideal for the transport industry.

Polyimide adhesives
Polyimides are one-part synthetic polymers that usually contain solvents. They are known for their strength, heat and chemical resistance, as well as performance in extremely high temperatures, as high as 500 degrees Celsius.

They are offered in two formulations, thermoset and thermoplastic, and are often used for coating or electronic insulation.

ADHESIVES BY PHYSICAL FORM

Adhesive physical form affects product application. Adhesives can be spread manually or using tools and equipment.

Below are the different physical forms available.

Paste
Adhesive pastes are often high in viscosity, thereby making them difficult to spread during the curing period. They are ideal for adhesions requiring gap filling and are usually applied with the use of tools, such as a caulking gun.

Liquid
Liquid is the most common form of adhesive. They are one of the easiest to apply but can leak or sag during the curing process. They often take longer to cure but can be applied in thin layers to help this process.

Film
Adhesive films are available in rolls or pre-cut lengths or shapes, provide easy application, and have no pot-life restrictions. They are available in thicknesses between 2 and 8 mm for different applications.

Pellets
Adhesives in the form of pellets are typically hot melt or thermosetting adhesives. These must usually be inserted into a hot melt gun or melted and sprayed.