Adhesives are of various types based on their physical and chemical composition. It is also based on the category of classification and load-bearing capability and is used in multiple industries.
FREMONT, CA: When choosing the right adhesive, there are many factors to consider. Each adhesive is designed for specific conditions & applications. Chemical composition, physical form, classification, and load-bearing capabilities can all be used to categorize adhesives.
There is an elaborate description of different adhesive categories and their uses:
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Adhesives based on Chemical composition: There are different types of adhesives based on their chemistries. Listed below are a few examples of chemical compositions.
Adhesives made of epoxy: Epoxies are structural adhesives. Most materials, including metals, ceramics, wood, and plastics, can be structurally bonded to them, as they are highly temperature and solvent-resistant.
Adhesives made of polyurethane: Polyurethane adhesives are polymer-based adhesives used for construction projects requiring high-strength bonding and permanent elasticity. Two-part adhesives are often available and have a variety of uses. In contrast to epoxy adhesives, they require moisture to set, so they can be used for projects where other types of glue are not appropriate.
Polyurethane adhesives, such as Adbond EX 5690, offer high flexibility, can be painted, and can be used in any weather. The transport industry benefits from polyurethanes because of this.
Physical Adhesives: Product application is affected by the adhesive physical form. Spreading adhesives can be done manually or with tools and equipment.
The different physical forms are listed below.
Copy and paste: In the curing process, adhesive pastes are often difficult to spread due to their high viscosity. A caulking gun is usually used to apply them to adhesions that require gap filling.
The liquid state: The most common form of adhesive is liquid. Although they are one of the easiest to apply, they can leak or sag during curing. Generally, they take longer to cure but can be applied in thin layers to speed up the process.
The film: The adhesive film is available in rolls or precut lengths and shapes, provides easy application and has no limitations on pot life. Depending on the application, they come in thicknesses ranging from 2 to 8 mm.
Classification of Adhesives: Structure is also a factor in categorizing adhesives.
Melts at high temperatures: As hot melt adhesives cool, they solidify into solid polymers and can be used to coat entire surfaces. Several industrial sectors value them for their eco-friendliness, safety, and shelf life. A hot melt adhesive can be EVA-based, APAO-based, or pressure-sensitive.
A polyurethane hot melt adhesive is also available, but it does not have the same properties as a standard hot melt adhesive.
Hot melt that reacts: Reactive hot melt adhesives generate additional chemical bonds after solidification, unlike non-reactive hot melt adhesives. As a result, the bonding is expanded, adhesion is stronger, and the product is more resistant to moisture, heat, and chemicals.
Sensitive to pressure: These adhesives are low-modulus elastomers, which means they can be used on wet surfaces with little pressure. Non-structural applications typically use them as tapes or labels since they are quite durable.
Contact Adhesives: Elastomeric contact adhesives are applied to both items being bonded together. As soon as the solvent evaporates, the items come into direct contact. In rubber cement and countertop laminates, these types of adhesives are found.
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