Sealants were used in stone-age cultures to water-proof
dwellings - archeology records show that bitumen was used
as early as 36,000 years ago. Naturally occuring bitumen
bound the walls of the ancient cities of both Jericho and
Babylon. It was also used as a sealant in the construction
of brick baths in India as early as 3000 B.C .
In more modern times, sealants (then commonly known as
"joint-fillers") have been used since the early
1900's, when heated tar was applied to seal joints between
concrete slabs. In the 1970s, the expectations of joint
fillers changed, and products were expected to minimize
water infiltration as well. At this time, the word "sealant"
became more common, and in essence, defined the switch in
Two other noteworthy dates in this brief history include:
1922/23 silica gel was first sold, and, around the same
time, lead solder was being phased out as a sealant in 'tin
can' joints. In 1941 a synthetic sealant was developed to
replace natural rubber bottle and can sealants - due to
a shortage of natural rubber.
What is a sealant:
Sealants are composed of two main types: silicone and polyurathanes.
The silicone sealants that are available at the hardware
store may be comprised of the following. Methyltriacetoxysilane
2%, Ethyltriacetoxysilane 2%, Silica or Silicon Dioxide
8-9%, and Polydimethysiloxane 85%. Polydimethylsiloxane
is the world’s most common silicone. Its applications range
from contact lenses and medical devices to elastomers, caulking
(sealing), lubricating oils and heat resistant tiles. Silicone
sealant's physical appearance can be described as: clear
paste with a consistency like toothpaste and with an acetic-acid
Polyurathanes are composed of long molecular chains - longer
than the molecules of silicones. These longer, more complex
chains mesh within each other more intricately, and this
gives them greater bonds within the sealant and to other
materials. As a result, they generally have greater shear
strength than silicone sealants and are less likely to break
along a glue line. The polyurethane sealants that are available
at the hardware store may be comprised of the following.
Polyurethane polymer (30 to 60%) Plasticiser (10 to 30%)
Filler (10 to 30%) Pigment (<10%) Xylene (<10 %). Its
physical properties can be described as: thixotropic, non
slump, coloured paste with a slight aromatic odour.
Care must be taken when using sealants - refer to the Material
Safety Data Sheet for each product. Typical hazards
include: Irritation to the nose and throat caused by the
vapor evolved during curing. Eye contact may cause intense
irritation and injury. Contact with the skin may cause skin
The following hyperlinks provide great resources for
teachers and students.
The following sealant websites links have very useful information
along with links to other sealants & adhesives sites.
GE Silicones has 3,500 employees at plants around
the world, and manufactures more than 4,000 products.
Bostik Findley Inc have lots of information and
datasheets online. (Adobe Reader is required to read the
.pdf files). Bostik Findley Inc has approx. 4,500 employees
with production facilities and sales operations in 36 countries
across six continents - making it one of the largest adhesive
and sealant company’s in the world.
Orica is a publicly owned Australian chemical company
employing around 8,000 staff across approximately 35 countries.
One of Orica's business areas, its 'consumer products',
includes the following well-known Australian brands. Dulux
paints, Cabots wood treatments (preservatives and
appearance improvers), and Selleys adhesives, sealants
and paint preparation products. (Orica's web site: www.orica.com.au)
The following links, then, represent some of the best information
that is available online!
Return >> to Adhesives
adhesive: a substance that unites or bonds.
sealant: a substance used to seal a surface to prevent
passage of a liquid or gas.
thixotropic: some gels become fluid when stirred
or shaken and return to a semisolid state upon standing.
. Oklahoma Geological Survey.
(undated). Earth Sciences Week : History of Petroleum Development.
[WWW Document] URL: www.ou.edu/special/ogs-pttc/earthsci/histpetr.htm
(visited October 2002).
. Public Works Magazine: Online
Edition. (2000). "An Overview of Joint Sealants for
Concrete Pavements" by Voigt, J. [WWW Document] URL:
(visited October 2002).
Note: This page is under
construction, and will be added to as time permits.
Copyright D. L. Christiansen [Last updated
Nov 2002] Images: respective copyright owners noted/cited.