Understanding the Difference Between Adhesive and Sealant

Adhesives are designed to bind materials together & seal them. It is important to use these construction chemicals according to their intended and instructed usages.

It is also important to consider the substrates & anticipated movement in a joint. This will ensure that the chosen adhesive or sealant will be suitable.

What is the Difference Between Adhesive and Sealant?

Despite the fact that the terms “adhesive” and “sealant” are often used interchangeably, it is important to understand the difference between these construction chemicals. The two work in a similar manner by bonding surfaces together, but they differ in the way they do this. The main difference is that adhesives offer a much more rigid and powerful feel, look, and strength than sealants due to their tightly cross-linked molecular structure.

This makes them better suited to applications needing surface-to-surface adhesion such as bonding metal to concrete. Sealants, on the other hand, are designed to fill gaps and cracks to protect the substrates from moisture, dirt, and other contaminants. The differences don’t end here, however. Both types of construction chemical are designed for different conditions and are formulated accordingly. For instance, adhesives are often formulated with additives that ensure they are water resistant and able to resist harsh weathering, while sealants are typically made of flexible materials such as silicones, polyurethanes, and acrylics that allow them to accommodate movement.

It is also essential to follow the correct installation procedures and abide by any manufacturer warranties that may apply. Abiding by these guidelines will help to ensure that the adhesive or sealant performs properly for its prescribed life span and qualifies for any warranty coverage. In addition, adhering to the recommended application temperatures and humidity levels will also make the adhesive or sealant last longer and prevent premature degradation.

What are the Types of Adhesives?

There are many different types of adhesives, each designed for specific conditions and applications. Generally, they can be categorized by their chemistry, physical form and load bearing capability.

Chemically, most adhesives are adhesive and sealant composed of polymers – large molecules that bond easily with surfaces. They are also sensitive to heat, melting and setting again when exposed to specific temperatures.

A thermoset adhesive is an example, as is epoxy resin – which is resistant to corrosion and moisture and can make a strong bond on metal. Phenol formaldehyde resins are another type of structural adhesive, used for laminating materials.

Anaerobic adhesives are the opposite of thermoset adhesives, curing in the absence of oxygen and moisture. They are used in products that need to be bonded and sealed quickly, such as product assembly or affixing electronic components.

Solvent-based adhesives are available as liquid, paste or pellets. Liquid adhesives are the easiest to use but can leak or sag during the curing process. They are also typically flammable, so special care and precautions are required.

Pellet-based hot melt adhesives are a popular option for industrial users because they are easy to apply. They can be inserted into a hot glue gun and heated to liquid, coating surfaces before they cool and set into a solid polymer. They can also be melted down and sprayed, so they are an ideal choice for large projects where the adhesive is constantly being applied.

What are the Types of Sealants?

Sealants are liquid products used to form a barrier or seal between surfaces or components. Like adhesives, there are many different types of sealants and each one has its own strengths and limitations based on the chemistry that it uses.

Polyurethane sealants are popular because of their superior strength and durability. They are also available in a variety of finishes to suit the substrate. Silicone sealants are also an option and they offer good elasticity, water resistance and heat aging resistance. They can be cured at room temperature and are compatible with most materials.

Latex sealants are commonly used in residential situations as they’re easy to use and inexpensive. However, their service life is relatively short and they have a difficult time accommodating movement. Acrylic solvent-based sealants are an excellent choice for low-movement joints as they have good adhesion, don’t shrink and resist UV.

There are also polysulfide sealants that are becoming increasingly popular for their elasticity and long lifespan. They are available in adhesive and sealant two special forms – gun grade and pour grade. Both can be applied using a PVC made gun with nozzles that are designed to deliver the sealant. A mixer is required for a two-part system and it’s important to ensure that the base and accelerator are properly mixed.

Other types of sealants are asphalt-based and they can be cured by heating or applying direct sunlight. Bitumen and tar are still widely used in civil engineering work but they’re quite old-fashioned with limited elongation at break and poor resistance to weathering.

What are the Benefits of Adhesives and Sealants?

Adhesives and sealants offer many benefits for both manufacturing and end-use applications. These include providing a stronger bond and creating a more secure seal, reducing corrosion and oxidation, improving the appearance of finished products, reducing weight, and making it easier to assemble components. The automotive industry, for example, uses adhesives to bind metals, plastics, and other materials in their assembly processes. In addition, they can help to reduce noise and vibration, improve safety, and increase efficiency in the production process.

Adhesive and sealant manufacturers use a range of chemicals to produce their products. These can include hot melt, reactive and water based adhesives as well as polyurethane-based sealants. These chemicals are available in a wide range of viscosities and strengths to suit different applications and substrates. They also come in a variety of curing styles. For instance, methyl methacrylate (MMA) adhesives cure gradually over time, while urethane-based adhesives often have what’s called a “snap cure” where the chemical reacts instantly to form a solid bond with the substrate.

To ensure that an adhesive or sealant works effectively, manufacturers must carefully select the right chemistry for the application. This will involve understanding the substrates and anticipated movement as well as weathering conditions. It’s also important to consider how long the product will need to work for, as this can affect its cost and ease of use. In addition, proper surface preparation is essential to ensuring a good bond and ideal curing conditions.