Sealant is a substance used to block the flow of liquid through the surface or joints or openings in a material, a type of mechanical seal. In building construction sealant is sometimes identical to caulking and also serves the purpose of blocking dust, noise and heat transmission. Sealants may be weak or strong, flexible or rigid, permanent or temporary. Sealants are not adhesives but some have adhesive qualities and are called sealant sealants or structural sealants.
Video Sealant
Histori
Sealants were first used in prehistory in the broadest sense such as mud, grass and reeds to cover dwellings from the weather such as daub and pallid and straw. Natural sealants and sealants include plant resins such as pine and birch pitch, asphalt, wax, tar, natural gum, mud (mire), lime mortar, lead, blood and eggs. In the 17th century, putty glazes were first used to cover windows made with linseed oil and lime, then other drying oils were also used to make oil-based putties often referred to as caulks . In the 1920s polymers such as acrylic polymers, butyl polymers and silicon polymers were first developed and used in sealants. In the 1960s, synthetic polymer-based sealants were widely available.
Maps Sealant
Function
The sealant, though it does not have great strength, carries a number of properties. They seal the top structures onto the substrate, and are highly effective in the process of waterproofing by keeping the moisture out (or in) the components in which they are used. They can provide thermal and acoustic insulation, and can serve as a fire barrier. They may have electrical properties as well. Sealants can also be used for simple tidying or filling. They are often called to perform some of these functions at once.
Sealant caulking has three basic functions: It fills the gap between two or more substrates; it forms a barrier through the physical properties of the sealant itself and by adhesion to the substrate; and, maintaining sealing properties for the expected lifetime, service conditions, and environment. Sealant performs these functions by means of the correct formulation to achieve specific application and property performance. In addition to adhesives, however, there are several functional alternatives to the sealing process. Solder or welding may be used as an alternative in a particular case, depending on the substrate and relative motion that the substrate will see in the service. However, the simplicity and reliability offered by organic elastomers usually makes them a clear choice for performing these functions.
Sealant type
A sealant may be a viscous material having little or no flow characteristics and a fixed one in which they are applied; or they can be thin and watery allowing it to penetrate the substrate by using capillaries. Anaerobic acrylic sealants (commonly referred to as impregnants) are most desirable, as they are needed to heal in the absence of air, unlike surface sealants that require air as part of a healing mechanism that converts the state into solid, once applied, and used to prevent air penetration , gas, noise, dust, fire, smoke, or liquids from one location through a barrier to another. Typically, sealants are used to close small openings that are difficult to cover with other materials, such as concrete, drywall, etc. Desirable sealant properties include insolubility, corrosion resistance, and adhesion. The use of sealants varies widely and sealants are used in many industries, for example, the construction, automotive, and aerospace industries.
This type of sealant falls between a sealer and a coating that has a higher strength, adhesive at one end, and very low putties of strength, wax, and caul on the other. Putties and caulks serve only one function - that is, to take up space and fill the cavities. Silicon is an example of a sealant - and has a proven longevity and is unaffected by UV or extreme weather or temperature.
See below for other common sealant types -
Common use area
Comparison with adhesive
The main difference between the adhesive and the sealant is that the sealant usually has a lower strength and a higher extension than the adhesive does. When sealants are used between substrates that have different thermal expansion coefficients or different elongations under pressure, they need to have sufficient flexibility and elongation. Sealants generally contain an inert filler and are usually formulated with elastomers to provide the required flexibility and elongation. They usually have a paste consistency to allow fill gaps between substrates. Low shrinkage after application is often required. Many adhesive technologies can be formulated into sealants.
References
Source of the article : Wikipedia
0 Comments