Choosing the Right Adhesive and Sealant

Adhesives are designed to keep two surfaces together over long periods and under varying amounts of stress. They are usually more rigid and durable than sealants.

Sealants are designed to close gaps and prevent things like dust, water, or dirt from entering. They are normally faster drying than adhesives and provide a sleek finish.

What is Adhesive and Sealant?

An adhesive is a substance that joins or binds two materials together while sealant is used to create an air and water tight condition between surfaces. Though these construction chemicals seem similar and are often used in the same manner the difference between them lies in their functionality, application and longevity. Choosing the right type of adhesive or sealant is crucial as it determines whether the final results meet expectations and requirements.

Adhesives and sealants are also different in how they harden. While sealants dry into a solid, one-dimensional structure, adhesives are thicker and form a bond that holds objects at a microscopic level. This allows them to maintain their strength and elongation/flexibility even when the object is pulled apart.

The bond between the adhesive and substrate occurs by either mechanical means, in which the glue works its way into small pores of the surface, or by one of several chemical mechanisms such as electrostatic or van der Waals forces that develop between molecules. The adhesive and substrate must be very close in order for the force of adhesion to develop, which is why it’s so important to follow manufacturer instructions when applying.

Additionally, all sealants and adhesives must be stored in a cool place and not in direct sunlight or heat, as this will affect their performance and life cycle. Abiding by these storage guidelines will ensure that the adhesive or sealant lasts for its prescribed and intended usage and is eligible for any warranty coverage.

Types of Adhesives and Sealants

The type of adhesive or sealant you select will depend on the materials you’re bonding, how much strength is required and the environment it’ll be used in. Always follow the instructions on the label to ensure the application and curing is successful.

Adhesives are rigid & strong and have a wide range of industrial & construction uses, including assembling machinery, tiling & glazing windows. They also serve to fill gaps and cracks between substrates. They can be a time and cost effective alternative to using metal fasteners.

Sealants are flexible & have a wider range of industrial and construction applications than adhesives, from sealing joints & gaps to adhesive and sealant blocking fluids, dust & dirt from entering or leaving an area. They can also be used to provide acoustical insulation, electrical properties or act as fire barriers.

There are a number of different types of sealants, including silicone, polyurethane & acrylates. Each of these products has their own distinct characteristics, but all offer similar benefits. Essentially, sealants are designed to withstand movement while adhering to surfaces – a property that makes them ideal for use in areas where there is a high level of pressure. They can be formulated to withstand extreme temperatures and chemical exposures too, and are available in various thicknesses to suit the application at hand.

Application of Adhesives and Sealants

The type of adhesive or sealant used depends on the application and environmental conditions it must withstand. Some factors to consider include the substrate materials, the types of stresses — compressive, tensile or torsion, intermittent or constant — and the thermal and chemical exposure. Specialized conditions may also require the bond to provide certain acoustic or electrical properties, act as a fire barrier or display a specific surface appearance.

In addition to the strength of the adhesive or sealant, its ability to resist crack propagation is also important. This is a significant challenge as crack surfaces in adhesively bonded structures tend to slide over one another rather than adhering to each other. Using an appropriate design procedure and geometry modifications can help reduce the amount of crack displacement, allowing for stable crack propagation in structurally acceptable modes.

Rigid bonding applications for adhesives include a wide variety of products adhesive and sealant and processes such as electric motor magnet bonding; telephone pole repair; bowling alley repair; woodworking and furniture manufacturing; automotive seam sealing, body panel bonding and trim pieces; aerospace sealant application; and medical device assembly.

Adhesives and sealants are also used in the prefabricated house industry for insulation panels, hybrid constructions and other elements. Additionally, specialized adhesives can be used in the marine industry for sealant and glue applications such as coating and adhesives for fuel/diesel exhaust fluid (DEF) lines.

Maintenance of Adhesives and Sealants

When used correctly, adhesives and sealants can play a critical role in improving equipment reliability and lowering maintenance and operational costs. With rapidly developing technologies and products, it’s important for businesses to stay on top of current trends to make sure they get the most out of these essential tools.

One key trend in the industry is that manufacturers will need to use adhesives and sealants that can resist the effects of moisture, chemicals and weather for long-life and durability. The chemistry of the bonding materials will also impact the working life and application techniques required.

Another key trend in the industry is that there will be an increase in demand for structural adhesives that provide good mechanical properties, such as elongation under stress and coefficient of thermal expansion. These new chemistries will allow for improved performance and reduced maintenance costs due to less frequent repairs and replacements of equipment.

Threadlocking sealants are a common and highly effective way to prevent vibration loosening of screw and bolt threads. These self-curing sealants fill gaps and voids in machining tolerances to create a solid filler, which significantly reduces loosening over time. This can help prevent catastrophic fatigue failures and lengthy system downtime, while saving energy costs by reducing pressure on mating components. These anaerobic sealants also provide a strong and permanent barrier against corrosion, water and other contaminants.