Sealant

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Self-leveling silicone firestop system used around pipe through-penetration in a two-hour fire-resistance rated concrete floor assembly. Self level silicone.jpg
Self-leveling silicone firestop system used around pipe through-penetration in a two-hour fire-resistance rated concrete floor assembly.

Sealant is a substance used to block the passage of fluids through openings in materials, [1] a type of mechanical seal. In building construction sealant is sometimes synonymous with caulk (especially if acrylic latex or polyurethane based) [2] and also serve the purposes of blocking dust, sound 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 adhesive-sealants or structural sealants.

Contents

History

Sealants were first used in prehistory in the broadest sense as mud, grass and reeds to seal dwellings from the weather [3] such as the daub in wattle and daub and thatching. Natural sealants and adhesive-sealants included plant resins such as pine pitch and birch pitch, bitumen, wax, tar, natural gum, clay (mud) mortar, lime mortar, lead, blood and egg. In the 17th century glazing putty was first used to seal window glass made with linseed oil and chalk, later other drying oils were also used to make oil-based putties. [4] In the 1920s, polymers such as acrylic polymers, butyl polymers and silicone polymers were first developed and used in sealants. By the 1960s, synthetic-polymer-based sealants were widely available. [5]

Function

Sealants, despite not having great strength, convey a number of properties. They seal top structures to the substrate, and are particularly effective in waterproofing processes by keeping moisture out (or in) the components in which they are used. They can provide thermal and acoustical insulation, and may serve as fire barriers. [6] [7] They may have electrical properties, as well. Sealants can also be used for simple smoothing or filling. They are often called upon to perform several of these functions at once.

A caulking sealant has three basic functions: It fills a 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 it maintains sealing properties for the expected lifetime, service conditions, and environments. The sealant performs these functions by way of correct formulation to achieve specific application and performance properties. Other than adhesives, however, there are few functional alternatives to the sealing process.[ citation needed ]

Soldering or welding can perhaps be used as alternatives in certain instances, depending on the substrates and the relative movement that the substrates will see in service. However, the simplicity and reliability offered by organic elastomers usually make them the clear choice for performing these functions.

Types

A sealant may be viscous material that has little or no flow characteristics and which stay where they are applied; or they can be thin and runny so as to allow it to penetrate the substrate by means of capillary action.

Anaerobic acrylic sealants (generally referred to as impregnants) are the most desirable, as they are required to cure in the absence of air, [8] unlike surface sealants that require air as part of the cure mechanism that changes state to become solid, once applied, and is used to prevent the penetration of air, gas, noise, dust, fire, smoke, or liquid from one location through a barrier into another.

Typically, sealants are used to close small openings that are difficult to shut with other materials, such as concrete, drywall, etc. Desirable properties of sealants include insolubility, corrosion resistance, and adhesion. Uses of sealants vary widely and sealants are used in many industries, for example, construction, automotive and aerospace industries.

Sealants can be categorized in accordance with varying criteria, e. g. in accordance with the reactivity of the product in the ready-to-use condition or on the basis of its mechanical behavior after installation. [9]

Often the intended use or the chemical basis is used to classify sealants, too. A typical classification system for most commonly used sealants is shown below.

Classification of sealants by reactivity and chemistry Classification of sealants by reactivity and chemistry.png
Classification of sealants by reactivity and chemistry

Types of sealants fall between the higher-strength, adhesive-derived sealers and coatings at one end, and extremely low-strength putties, waxes, and caulks at the other. Putties and caulks serve only one function – i.e., to take up space and fill voids. Sealants maybe based on silicone.

Other common types of sealants:

Common areas of use

Aerospace sealants

Comparison with adhesives

The main difference between adhesives and sealants is that sealants typically have lower strength and higher elongation than adhesives do. When sealants are used between substrates having different thermal coefficients of expansion or differing elongation under stress, they need to have adequate flexibility and elongation. Sealants generally contain inert filler material and are usually formulated with an elastomer to give the required flexibility and elongation. They usually have a paste consistency to allow filling of gaps between substrates. Low shrinkage after application is often required. Sealants also typically require a sufficient compression set, especially when the sealant is a foam gasket. Many adhesive technologies can be formulated into sealants.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Adhesive</span> Non-metallic material used to bond various materials together

Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation.

<span class="mw-page-title-main">Acrylic paint</span> Water resistant paint type meant for canvases

Acrylic paint is a fast-drying paint made of pigment suspended in acrylic polymer emulsion and plasticizers, silicone oils, defoamers, stabilizers, or metal soaps. Most acrylic paints are water-based, but become water-resistant when dry. Depending on how much the paint is diluted with water, or modified with acrylic gels, mediums, or pastes, the finished acrylic painting can resemble a watercolor, a gouache, or an oil painting, or have its own unique characteristics not attainable with other media and are meant for canvases.

<span class="mw-page-title-main">Silicone</span> Family of polymers of the repeating form [R2Si–O–SiR2]

In organosilicon and polymer chemistry, a silicone or polysiloxane is a polymer composed of repeating units of siloxane. They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking utensils, thermal insulation, and electrical insulation. Some common forms include silicone oil, grease, rubber, resin, and caulk.

<span class="mw-page-title-main">Grout</span> Building material

Grout is a dense fluid that hardens used to fill gaps or as reinforcement in existing structures. Grout is generally a mixture of water, cement, and sand, and is employed in pressure grouting, embedding rebar in masonry walls, connecting sections of precast concrete, filling voids, and sealing joints such as those between tiles. Common uses for grout in the household include filling in tiles of shower floors and kitchen tiles. It is often color tinted when it has to be kept visible and sometimes includes fine gravel when being used to fill large spaces. Unlike other structural pastes such as plaster or joint compound, correctly mixed and applied grout forms a water-resistant seal.

<span class="mw-page-title-main">Caulk</span> Flexible material used in construction to seal joints

Caulk or, less frequently, caulking is a material used to seal joints or seams against leakage in various structures and piping.

Putty is a material with high plasticity, similar in texture to clay or dough, typically used in domestic construction and repair as a sealant or filler. Although some types of putty slowly polymerise and become stiff, many putties can be reworked indefinitely, in contrast to other types of filler which typically set solid relatively rapidly.

<span class="mw-page-title-main">Polydimethylsiloxane</span> Chemical compound

Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, is a silicone polymer with a wide variety of uses, from cosmetics to industrial lubrication.

<span class="mw-page-title-main">Butyl rubber</span> Synthetic rubber; a copolymer of isobutylene with isoprene

Butyl rubber, sometimes just called "butyl", is a synthetic rubber, a copolymer of isobutylene with isoprene. The abbreviation IIR stands for isobutylene isoprene rubber. Polyisobutylene, also known as "PIB" or polyisobutene, (C4H8)n, is the homopolymer of isobutylene, or 2-methyl-1-propene, on which butyl rubber is based. Butyl rubber is produced by polymerization of about 98% of isobutylene with about 2% of isoprene. Structurally, polyisobutylene resembles polypropylene, but has two methyl groups substituted on every other carbon atom, rather than one. Polyisobutylene is a colorless to light yellow viscoelastic material. It is generally odorless and tasteless, though it may exhibit a slight characteristic odor.

Nitrile rubber, also known as nitrile butadiene rubber, NBR, Buna-N, and acrylonitrile butadiene rubber, is a synthetic rubber derived from acrylonitrile (ACN) and butadiene. Trade names include Perbunan, Nipol, Krynac and Europrene. This rubber is unusual in being resistant to oil, fuel, and other chemicals.

<span class="mw-page-title-main">Hot-melt adhesive</span> Glue applied by heating

Hot-melt adhesive (HMA), also known as hot glue, is a form of thermoplastic adhesive that is commonly sold as solid cylindrical sticks of various diameters designed to be applied using a hot glue gun. The gun uses a continuous-duty heating element to melt the plastic glue, which the user pushes through the gun either with a mechanical trigger mechanism on the gun, or with direct finger pressure. The glue squeezed out of the heated nozzle is initially hot enough to burn and even blister skin. The glue is sticky when hot, and solidifies in a few seconds to one minute. Hot-melt adhesives can also be applied by dipping or spraying, and are popular with hobbyists and crafters both for affixing and as an inexpensive alternative to resin casting.

<span class="mw-page-title-main">Silicone rubber</span> Elastomer

Silicone rubber is an elastomer composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations. Silicone rubbers are often one- or two-part polymers, and may contain fillers to improve properties or reduce cost. Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and temperatures from −55 to 300 °C while still maintaining its useful properties. Due to these properties and its ease of manufacturing and shaping, silicone rubber can be found in a wide variety of products, including voltage line insulators; automotive applications; cooking, baking, and food storage products; apparel such as undergarments, sportswear, and footwear; electronics; medical devices and implants; and in home repair and hardware, in products such as silicone sealants.

<span class="mw-page-title-main">Acrylate polymer</span> Group of polymers prepared from acrylate monomers

An acrylate polymer is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity.

LORD Corporation is a diversified technology and manufacturing company that develops adhesives, coatings, motion management devices, and sensing technologies for industries such as aerospace, automotive, oil and gas, and industrial. With world headquarters in Cary, North Carolina, LORD has approximately 3,100 employees in 26 countries and operates 19 manufacturing facilities and 10 R&D centers worldwide. As of October 30, 2019, the company has been acquired by Parker Hannifin.

<span class="mw-page-title-main">Soudal</span>

Soudal is a Belgian company whose headquarters is located in Turnhout (Belgium). The company has developed into one of the most important independent producers of silicone and caulks, polyurethane-foams, and adhesives in Europe.

<span class="mw-page-title-main">DAP Products</span>

DAP Products, Inc. is a manufacturer of latex caulks, silicone sealants, adhesives, insulating foams, and patch & repair products. DAP has been made in the USA since 1864 and headquartered in Baltimore, MD since 1998.

RTV silicone is a type of silicone rubber that cures at room temperature. It is available as a one-component product, or mixed from two components. Manufacturers provide it in a range of hardnesses from very soft to medium—usually from 15 to 40 Shore A. RTV silicones can be cured with a catalyst consisting of either platinum or a tin compound such as dibutyltin dilaurate. Applications include low-temperature over-molding, making molds for reproducing, and lens applications for some optically clear grades. It is also used widely in the automotive industry as an adhesive and sealant, for example to create gaskets in-place.

The chemistry of pressure-sensitive adhesives describes the chemical science associated with pressure-sensitive adhesives (PSA). PSA tapes and labels have become an important part of everyday life. These rely on adhesive material affixed to a backing such as paper or plastic film.

Butyl acrylate is an organic compound with the formula C4H9O2CCH=CH2. A colorless liquid, it is the butyl ester of acrylic acid. It is used commercially on a large scale as a precursor to poly(butyl acrylate). Especially as copolymers, such materials are used in paints, sealants, coatings, adhesives, fuel, textiles, plastics, and caulk.

Adhesive bonding is a joining technique used in the manufacture and repair of a wide range of products. Along with welding and soldering, adhesive bonding is one of the basic joining processes. In this technique, components are bonded together using adhesives. The broad range of types of adhesives available allows numerous materials to be bonded together in products as diverse as vehicles, mobile phones, personal care products, buildings, computers and medical devices.

References

  1. ↑ "Sealant", Oxford English Dictionary Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009
  2. ↑ "How to Choose the Right Caulk or Sealant for Your Next Plumbing Project | Oatey". www.oatey.com. Archived from the original on 2023-03-25. Retrieved 2023-03-25.
  3. ↑ Klosowski, Jerome M.; Wolf, Anreas T. (2009). "The History of Selants". In Mittal, K.L.; Pizzi, A. (eds.). Handbook of Sealant Technology. CRC Press. p. 4. ISBN   9781420008630. Archived from the original on 2021-04-11. Retrieved 2021-04-11– via Google Books.
  4. ↑ Klosowski, Jerome M.; Wolf, Anreas T. (2009). "The History of Selants". In Mittal, K.L.; Pizzi, A. (eds.). Handbook of Sealant Technology. CRC Press. p. 5. ISBN   9781420008630. Archived from the original on 2021-04-11. Retrieved 2021-04-11– via Google Books.
  5. ↑ Klosowski, Jerome M.; Wolf, Anreas T. (2009). "The History of Selants". In Mittal, K.L.; Pizzi, A. (eds.). Handbook of Sealant Technology. CRC Press. p. 7. ISBN   9781420008630. Archived from the original on 2021-04-11. Retrieved 2021-04-11– via Google Books.
  6. ↑ Slone, Herbert; Fox, Art (March 12, 2018). "Best practices for masonry wall systems and insulation". constructioncanada.net. Archived from the original on April 11, 2021. Retrieved April 11, 2021.
  7. ↑ Guertin, Mike. "Building Soundproof Walls". Fine Home Building (266 April/May 2017). Archived from the original on April 11, 2021. Retrieved April 11, 2021.
  8. ↑ "Adhesive Bonding". Handbook of Plastics Joining: A Practical Guide (2d ed.). William Andrew. 2008. p. 145. ISBN   978-0-8155-1581-4. Archived from the original on 2021-04-11. Retrieved 2021-04-11.
  9. ↑ Manfred Pröbster, Industrial Sealants - Fundamentals, selection and applications, Verlag Moderne Industrie 2004
  10. 1 2 3 "5 Sealing Technologies Commonly Used by Manufacturers Today". roboticsandautomationnews.com. May 22, 2020. Archived from the original on April 11, 2021. Retrieved April 11, 2021.
  11. ↑ Roberts, Dormie (March 18, 2021). "Early Season Best Practices for Sealcoating". forconstructionpros.com. Archived from the original on April 11, 2021. Retrieved April 11, 2021.
  12. ↑ "Russian Cosmonauts Take Spacewalk to Check Site of Capsule Leak". Voice of America . December 11, 2018. Archived from the original on April 11, 2021. Retrieved April 11, 2021.
  13. ↑ World of fresh water : a resource for studying issues of freshwater research. Diane Publishing. 1997. p. 9. ISBN   9781428903814. Archived from the original on 2021-04-11. Retrieved 2021-04-11– via Google Books.
  14. ↑ Jenkins, Richard (April 8, 2021). "Best Outdoor Wood Sealers Comparison and Buyer's Guide". thatpainter.com. Archived from the original on April 11, 2021. Retrieved April 11, 2021.
  15. ↑ "D Aircraft Dapco 18-4F Firewall Sealant | NSL Aerospace". Archived from the original on 2020-09-15. Retrieved 2020-03-13.
  16. ↑ "WS-8020 Class B Sealant - High Temperature Fuel Tank Sealant | NSL Aerospace". Archived from the original on 2020-07-25. Retrieved 2020-03-13.
  17. ↑ "WS-8010 Class B Sealants - Aircraft Access Door Sealant PMF | NSL Aerospace". Archived from the original on 2020-08-12. Retrieved 2020-03-13.
  18. ↑ "Dapco 72 Rapid Curing Windshield Sealant | NSL Aerospace". Archived from the original on 2020-07-25. Retrieved 2020-03-13.
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