Whether you are a hardcore do-it-yourselfer or a veteran tradesman, you may be familiar with sealants. Sealants are primarily used to make spaces watertight or airtight. They are versatile and have a wide range of applications, but you have to get the right kind of sealant for the material you’re working with. However, with the different types of sealants in the market, it may not be easy to pick the right one for the job.
This article will give you a general overview of what sealants are and how they relate to adhesives. It will also list down the common types of sealants and their applications and the types of curing processes they should undergo. Read the infographic below to get started.
What are sealants?
A sealant is a substance that fills gaps between two surfaces to form a barrier against water and air as it hardens. Sealants vary in characteristics; some are flexible, some are rigid, and some have adhesive properties, although others may not have these qualities. Some types of sealants have desirable secondary properties such as insulation from sound, heat, and fire.
Sealants vs. Adhesives
While there is quite an overlap between the properties of sealants and adhesives, they are two different things that you should not substitute with each other.
Adhesives are primarily used for bonding two surfaces together. Note that some adhesives can create an airtight and watertight seal. In addition, some sealants have adhering properties, which leads some to believe that both can be used interchangeably.
In general, sealants are pliable and form weaker bonds, while adhesives are more rigid and form stronger bonds. That is why you should never use a sealant for a task that is meant for adhesives.
Common Types of Sealants
There are numerous types of sealants for different purposes. Here is a list of the most common ones that you might encounter:
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Acoustic sealants
Acoustic sealants are made out of a semi-liquid latex that hardens into a rubbery material when dried. As the name implies, it has soundproofing properties that prevent noise from entering through the gaps of a room. This type of sealant is perfect for applying around window frames, walls, and ceilings.
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Acrylic sealants
Acrylic sealants are affordable acrylic polymer-based sealants used mainly for caulking and filling gaps to seal them from water and air. When the sealant hardens, it remains paintable so it’s easy to conceal.
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Adhesive sealants
An adhesive sealant is a two-in-one product that provides both sealing and adhering properties. However, its bonding strength is weaker than traditional adhesives, so it is best to use this for light items such as glass, mirrors, and polystyrene.
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Butyl rubber sealants
Butyl rubber sealants are elastomer-based sealants that are strong, durable, and have good aging and weathering characteristics. Moreover, this sealant can be applied to various materials.
What makes it unique is that it does not require a curing process. Instead, it retains a flexible chewing gum-like consistency throughout its life, making it ideal for sealing gutters, corrugated roofing, pipes, and spouts.
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Elastic sealants
An elastic sealant, more commonly known as elastomeric sealant, comes in a liquid form with a thick and rubbery consistency. It is used mostly to fix water leaks or as a waterproofing membrane for large surfaces.
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Electronic sealants
Electronic sealants are silicon-based sealants made specifically for electronic components such as circuit boards and other sensitive electronics. This sealant is quick-curing and protects electronic parts against thermal and physical shocks.
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Floor sealants
A floor sealant is a polymer-based coating designed to protect floors made of porous materials (e.g., bricks, vinyl, and concrete) to reduce wear and tear and prevent water damage. This type of sealant seeps deeper through the porous material of patio flooring to prevent moisture from perforating and reducing bacterial growth.
However, for outdoor applications, you may use stone and tile sealants and patio sealants instead because they are designed to survive harsh outdoor environments.
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Foam sealants
Foam sealants are used to close up significant gaps on a surface. To cover a wide area, the foam expands after it has been sprayed through a spray can. Once it hardens, the excess layers can be trimmed and filed off, and eventually painted over. You can also use foam sealants for securing loose fixtures and sealing window and door gaps.
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Latex sealants
Latex sealants are water-based, easy to use, and affordable. Plus, they have a wide range of applications. They are mainly used for residential and light commercial applications and can be easily painted over with latex paint.
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Metal sealants
Metal sealants are usually made of silicone or polyurethane. Aside from sealing metal surfaces from air and water, metal sealants are flexible to allow for the slight contraction and expansion of metal surfaces due to temperature changes. This type of sealant is used for roof steps, roof-to-wall transitions, gutter seams, and similar applications.
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Polysulfide sealants
Polysulfide sealants are made up of chains of sulfur atoms and are designed to endure lengthy exposures to water. Specialists mostly use this sealant on swimming pools, fountains, storage tanks, and wastewater treatment facilities.
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Polyurethane sealants
Polyurethane sealants adhere to most surfaces and form a strong bond even without a primer. They can also be painted with latex paint once dried. However, they can be expensive and difficult to apply. Because of this, polyurethane sealants are used mostly for industrial and commercial applications.
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Silicone sealants
Silicone sealants are flexible and offer good adhesion to common building materials, but they require a primer before application and are unpaintable, unlike polyurethane sealants. However, since silicone is an inorganic compound, it is excellent at resisting temperature changes and UV fading.
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Urethane sealants
Urethane sealants are as flexible and as durable as silicone sealants. However, you cannot use them for polycarbonate plastics. Moreover, you need to paint them once dried as they are highly susceptible to degradation when exposed to UV light.
Types of Sealant Curing Process
Since sealants are made up of different combinations of chemicals and materials, they require different curing processes to achieve their final shape and hardness. Here is a list of the different types of sealant curing processes used today.
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Thermal curing
Some sealants do not reach their final form until they have been heated to a specific temperature. Thermal curing sealants are generally divided into two: thermosets and thermoplastics.
For thermosetting sealants, the heat does not necessarily need to come from an external source. The heat is often generated by a reaction of the resin and a curing agent. The resulting cured seal is resistant to heat and water. In contrast, thermoplastics become pliable when heated and harden after it has cooled off.
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Evaporation
Most water-based and solvent-based sealants require the evaporation curing process, where the sealant hardens once the moisture or the solvent has evaporated from the solution.
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Anaerobic curing
As the name implies, anaerobic curing sealants cure in the absence of air. The anaerobic environment is created as the two surfaces to be sealed are jointed. This is mostly used for sealing metals and glass.
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UV light/radiation
Some sealants need to be exposed under intense UV light or an electron beam to finish the curing process. This results in a quicker curing time and is much more energy-efficient compared to thermal curing. Acrylic sealants mostly use this method.
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Moisture curing
In this method, sealants need to be at room temperature and use moisture from the air to cure. The curing time varies depending on the kind of sealant used.
How Sealants are Used in Various Industries
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Construction, renovation, and DIY
Sealants are mostly used in the construction industry as caulking to block liquid, dust, heat, and sound from either escaping the building or getting through it. They are mostly used to seal joints, shore up cracks, and laminate porous materials for protection.
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Electronics
In the electronics industry, sealants are used to protect and provide structural integrity to sensitive electronic parts physically. They also offer heat transfer and electric conductivity functions to optimize the performance of the electronics.
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Automotive
Sealants are widely used in the automotive industry for a variety of purposes. Since modern cars are made of composite materials, they cannot be welded together like older cars. Hence, sealants and adhesives are widely used instead. They are applied to the interior to soundproof the car, seal the gaps when materials are joined together, and protect the electronics fitted into the modern car.
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Aerospace
Sealants are also widely used in the aerospace industry from the interior, exterior, and the engine itself. Due to stringent regulations in this industry, the sealants in use are specialty products that meet safety requirements and offer high protection against heat, corrosion, abrasion, and structural fatigue.
Know Your Sealants
Sealants are versatile materials that have wide applications in many industries. They play a big role in making the world safe and livable.
Are you looking for top-quality sealants? You’re in the right place! Simplex is a premier distributor of industrial sealant brands and premium quality parts in the Philippines. We will gladly provide everything that you need. Visit our shop today to get started!
