Durable seals with industrial sealants
Sealant is a chemical product, a mechanical seal widely used in industrial applications. Sealants fill gaps, cracks and openings that otherwise might cause seepage of liquids, gas or other unwanted matter. When two or more parts are put together, gaps are inevitable. This is where industrial sealants come into picture filling the gaps.
Note that sealants are no alternative to adhesives even though some sealants, such as epoxies and specially formulated polymers, have adhesive properties.
Curing industrial sealants
Curing is the process which hardens the sealant to its final shape and strength. There are several types of curing processes and curing times which are dependent on the used sealant. Some industrial sealants cure in few minutes whereas others some may require weeks to by completely hardened.
The main types of curing are as listed below:
- Ambient temperature: the ambient curing sealants are applied to the joint and let untouched to allow them to cure in room temperature using the moisture in the air or material to cure. The curing time varies from 30 minutes to 4 hours depending on the product, the thickness of the seal and the ambient humidity.
- Thermal curing: thermal curing sealants do not reach their final strength and toughness before they are allowed to harden under high heat specified for each product. Thermal cure sealants exist as thermosets which do not soften we reheated, and thermoplastics which can be reshaped when heated again.
- UV/Radiation: some sealants are cured using UV light or electron beam instead of heat. The UV and EB curing sealants have shorter curing time than thermally cured sealants and the curing demands less energy consumption.
- Anaerobic curing: the anaerobic curing sealants cure in the absence of oxygen. They are often used in joining metal parts exposing them to metal ions.
The 5 main types of industrial sealants
Currently, there are more than 40 different types of industrial sealants available. However, the list of the most used sealants is much shorter: here we will introduce the 5 most common industrial sealants looking into their properties and uses throughout industries. You can receive more information on these or any other type of industrial sealants by contacting us.
1. Polymer based sealants
Description: polymer based sealants are a group of products including polyester, polyamide, polysulfide, vinyl and polyurethane sealants. They are most commonly cured in ambient temperature but allow for other curing methods such as thermal and anaerobic curing.
Properties: polymer sealants form permanently flexible seals, which makes them ideal for joints that experience movement.
Industrial uses: polymer sealants are the most common in locations requiring expansion joints. Brickwork and bridge joints also use polymer seals, and polymer glazing can be used for capping glazing purposes.
2. Phenolic sealants
Description: phenolic sealants are usually realized as a combination of phenol and formaldehyde. These sealants not only seal joints but also provide effective bonding. Phenolic sealant is also the only type of sealant that exists as powder, liquid and films.
Properties: phenolic sealants are especially known for their resistance to high temperatures and temperature fluctuation. They also have adhesive properties.
Industrial uses: phenolic sealants are used in applications involving sealing and bonding plywood, constructing buildings and in appliance industry.
3. Epoxy sealants
Description: when extreme strength and toughness is sought for, epoxy sealant is the solution. Epoxy sealants are usually supplies as two component systems consisting of a resin and a hardener, just like epoxy adhesives. They are mixed together prior to application at a rate set specifically for each product. Epoxy sealants cure in room temperature, but sometimes additional heat is required to harden the thermosetting epoxies.
Properties: epoxies are best known for their extreme strength and toughness. They also make up one of the few sealants that have exceptional adhesive properties.
Industrial uses: due to their strength epoxies are used across industries including automotive, marine and aviation. They also provide exceptional electrical insulation making them perfect for electronics.
4. Acrylic sealants
Description: acrylic sealants are produced by acrylic acid via catalytic reaction. These sealants are curable through various methods. When thermally cured, the curing time is the lowest.
Properties: acrylic sealants have good bonding properties and they eliminate all kinds of infiltration by foreign particles. Additionally, they are paintable, odorless and flexible. Acrylic sealant is also an option for outdoor applications since it is resistant to the elements. Note that acrylics are prone to chemical damage and should not be applied where chemical exposure is likely.
Industrial uses: the most common applications of acrylic sealant includes sealing doors and window frames. They are also used in many domestic applications.
5. Silicone based sealants
Description: silicone based sealants are the most common industrial sealants as they are versatile, strong and affordable. They have a life expectancy of 10-20 years. Silicone based sealants exist in two types: neutral cure and acetoxy.
Properties: silicone based sealing solutions are strong and watertight. They can also be given special properties such as heat and chemical resistance.
Industrial uses: the range of industrial uses of silicone sealing systems is broad. They are suitable for example for glazing as a structural sealant and sealing electric sockets.
Material compatibility of sealants in industrial applications
When choosing an industrial sealant, one of the most important things to consider is the product´s compatibility with the planned substrate. To enlighten the possibilities we have created a list of the most common substrates and the sealant types compatible with them.
- Concrete: one of the most common construction materials, concrete, can be sealed with polymer sealants.
- Metal: metal joints are usually sealed with silicone and polymer sealants. Silicone works especially well on aluminum, iron and steel.
- Porous materials: sealants with high viscosity or gelly structure work the best on porous surfaces. Silicone, polymers and epoxy are commonly used.
- Textiles: phenolic and silicone based sealants work the best on textile.
- Plastics: silicone and polymer sealants perform the best on plastic surfaces depending on the composition of the plastic.
- Ceramics: epoxy silicone and acrylic sealants bring the best results on non-metallic ceramic surfaces.
More information about industrial sealing solutions
Do you need assistance in choosing the right industrial sealant, or have you chosen one and would like to find the best product? Contact us and let our experts help you find the best product for your application.