HEAT
Activated carbon technology has been widely used throughout many industries, in fact, it is largely
applied to things we use on a daily basis. Water purification, soda filtration, medical uses and
environmental cleanup are just a few examples of ways activated carbon plays a role in our everyday
lives. Activated carbon is also used largely as one of the most effective ways to remove foul odors
from their source. This knowledge led to the use of activated carbon in fabrics, especially for hunters
and wildlife enthusiasts.
Activated carbon works through the process of physical adsorption. This means that in the fabric
of clothing the carbon creates a strong bond that traps odor molecules produced by the body. One
of the key features of activated carbon is all of the crevices or pores it has in its structure that odor
molecules are retained. To picture how this process works imagine tiny strands of odor molecules
that are generated by the human body floating around. Now imagine that the activated carbon in
the fabric is like microscopic Velcro. When the floating odor molecules come into contact with the
activated carbon they are held there until the product is reactivated.
Since activated carbon in fabric uses physical adsorption all that is needed to reactivate it is enough
heat to dissipate or remove an abundance of odor molecules from the pores of the carbon. The
amount of heat needed in this process can be supplied by an average house hold dryer. Although
reactivation does not fully remove all of the odor molecules from the fabric it is important that it is
understood the surface area of carbon is extremely large. According to Shasanka Sekhar and a
study done at Visveswaraya Technological University in Belgaum, one gram of activated carbon
has the surface area of roughly two tennis courts. So even though not all of the odor molecules are
removed during reactivation, there is plenty of surface area for many more odor molecules to be
adsorbed over many hours between reactivation cycles.
The main reasons that activated carbon is considered the most effective controller of human odor is
due to its ability to adsorb such a wide range and large amounts of odor molecules and compounds.
To really put things in perspective a study done by Dr. Don Thompson, professor at North Carolina
State University, found that over a thousand different compounds were identified in the inside of
a shoe from the human foot alone. So you can imagine if that many compounds comes from the
foot, when you consider the entire body you need something that can adsorb as many different
kinds of compounds as possible. This is what activated carbon provides and why it is known as the
“universal adsorbent”. It is a technology that spans the broad spectrum of different kinds of odor
molecules coming from the body by adsorbing virtually all types of odors.
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OUTER SHELL W/
ACTIVATED CARBON
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Although activated carbon is considered by many to be the most effective technology in odor
control, there is some maintenance that needs to be done in order to keep its effectiveness. Some
special care includes airtight storage and special non-scented laundry detergent. Also, it needs to
be reactivated periodically by regular tumbling in a dryer. The benefit of reactivation is it keeps the
carbon effective and reusable over and over.
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HEAT
Antimicrobials are a substance that kills and prevents the growth of bacteria. The uses of
antimicrobials are vast in today’s society. Antimicrobials are used in common medicine such as
penicillin and other antibiotics that target and kill bacteria, food products such as lactic and citric
acids and in fabrics of clothing to control human odor. These are just a few examples of how
antimicrobials play a role in our everyday lives.
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ANTIMICROBIAL
TREATMENT
The basic way antimicrobials work in fabrics is they are structured to target and reduce the
bacteria that causes odor by destroying cell membranes and reduces reproduction. They do this
by being applied to the surface or being interwoven in the thread of the fabric. Once odor causing
bacteria from the body comes into contact with the antimicrobial treated fabric, the antimicrobials
begin attacking the bacteria and prevent it from multiplying and spreading to form more bacteria.
There are basically three antimicrobial technologies used in fabrics: oxy technology, silver thread
technology, and AEGIS technology. Though all three are designed to achieve the same result, they
function in different ways.
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OXY ION TECHNOLOGY uses oxygen to attack and neutralize bacteria and
SILVER is used in a variety of ways, two of which are in medicine as an antibiotic
AEGIS TECHNOLOGY is another antimicrobial that can be found throughout
odor molecules. The word oxidize means removing electrons from an atom or
molecule, in this case odor molecules, leaving behind only oxides that are basically
neutralized. Oxy technology is used for odor control by a device or machine that
generates ozone gas that oxidizes odor molecules within a certain distance of the
machine. To get a better idea of the way this process is supposed to work, picture
a waterfall or curtain of ozone that is cast out of the machine. The ozone that is
generated is heavier than the odor molecules so it falls faster creating a curtain that
blocks active odor molecules from being cast out or beyond a certain area.
and in fabric to control human odor. It is typically applied to fabric in two ways, by
embedding tiny microscopic ions into the thread or by coating the thread itself. In
some cases it is believed that by incorporating silver into fabrics it strengthens the
fabric as well as kills bacteria. The silver technology attacks living bacteria that is
generated by the body. It does this by a process known as leaching. The process
of leaching involves silver ion release that penetrates the bacteria cell structure and
connects to the DNA within the bacteria killing the cell. This prevents the bacteria
that cause some of the human odor from reproducing and not allowing it to become
a strong source of odor itself.
many different industries and products. Aegis is used in things like surgical curtains in
hospitals, snowboarding and skiing boots and accessories, hiking boots, underwear,
socks, carpeting and more. Like the other antimicrobials, Aegis’ sole purpose is to
target and kill odor causing bacteria. What sets Aegis apart from other antimicrobials
is it is the only antimicrobial technology that chemically bonds to the surface of the
fabric. Essentially what makes Aegis technology work is an electrical charge. This
charge is colorless and odorless. The positive charge creates a chemical bond to
the surface of the fabric it is intended to protect. Because it is bonded, the charged
electrical thread that controls the growth of bacteria stays strongly attached to the
fabrics surface minimizing dissipation.
A benefit of oxy ion technology is it targets a wide range of odors. This is useful
because you don’t have to worry about the technology working on only a handful of
types of odors, similar to cyclodextrin and antimicrobials. The negatives to oxy ion
technology are that some studies have shown that in order for oxy technology to be
effective on the odor molecules given off by the body the ozone gas levels would
have to be between five and ten times higher than the public health standards to
prevent the molecules from surviving once the ozone technology is removed. (Dyas,
et al. 1983; Foarde et al., 1997)
Also, an ozone generator is required to be carried into the field which can be
cumbersome. Anyone with a heart condition or breathing issues is discouraged from
using oxy ion technology so it should not be used by everyone. These odor control
machines require batteries or electricity to power them which can get expensive.
Another down fall is when the oxy ion technology is used outdoors the machines
effectiveness is reduced in still or high wind conditions.
Silver is recognized by the Environmental Protection Agency (EPA) as one of the
most effective antimicrobials available. Some other benefits of silver technology are
its natural and not found harmful to humans. Silver technology fabrics do not have
to be reactivated in order to remain effective, but requires normal laundering. Silver
attacks bacteria on contact to stop it from multiplying before odors can generate
from bacteria. Although there are benefits to the strength and function of the use of
silver in controlling human odor, there are also attributes to be careful of and keep
in mind.
Silver leaches and can come out of the fabric during washing causing the fabric to
be less effective. As well as antimicrobials, another area where silver technology
falls short is it only targets living bacteria; it does not have a defense against odor
molecules generated by dead bacteria or any odors not generated by bacteria. Also,
depending on how the silver is applied to the fabric, it can cause skin irritation.
To help you get a better idea of what is going on here try to imagine that this bonded
layer that protects the fabric is a layer of electrically charged needles or spikes.
When a bacteria cell comes into contact with this layer of spikes, the treated surface
punctures the bacterial cell and shocks it. Even though the protective layer punctured
the cell and killed it, nothing was actually transferred from the antimicrobial into the
now dead cell so the protective layer does not lose its energy or change. One of
the most beneficial attributes to Aegis technology is that it targets the widest variety
of odor causing bacteria. It is also one of the most effective and longest lasting
antimicrobials due to the electrical bond that holds it to the fabric that no other
antimicrobial can do as effectively. However, it shares common down falls with the
other antimicrobials; it does not adsorb any odors.
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CYCLODEXTRIN
HEAT
Cyclodextrins are cone shaped molecules that are made up of starch molecules and sugar rings.
Cyclodextrin molecules exist in nature, but they can also be artificially made by manipulating starch
molecules. Cyclodextrins can be applied to fibers to make fabrics and can also be found in foams.
The purpose for applying cyclodextrins to fabrics is to absorb odors caused by the human body.
Molecules such as butane and propane are the most commonly attracted molecules by the center
of cyclodextrins.
The benefits to using cyclodextrin technology are that cyclodextrin molecules naturally stack on
top of each other; this optimizes the effectiveness by having a better chance of absorbing odor
molecules. Another benefit is when cyclodextrin absorbs an odor molecule they can change shape
in order to hold the odor molecule more effectively.
Some of the negative aspects of cyclodextrin technology are that odor molecules can be all different
shapes and sizes and if odor molecules are too small they can pass right through the cyclodextrin
molecule. On the other hand if an odor molecule is too big it can bounce off the structure. So in
either case, too big or too small, odor molecules need to fit into a certain size range in order for
cyclodextrins to be effective meaning not all odors are adsorbed or removed. Another setback to
cyclodextrins is that even though there is currently testing being done for effectiveness in other
fabrics, they have been found to chemically bond to cotton fabrics only. This means that the
application for cyclodextrins on technical fabrics is incapable of withstanding washing machines,
dryers, etc. and still be effective. However, even though cotton is the most effective fabric it is still
found that the cyclodextrin molecules can wash out of the cotton fabrics after repeated washings.
BACTERIA
CYCLODEXTRIN
In order for cyclodextrins to absorb odors
the molecules must fit snugly. If the odor
molecule is too large or small it will bounce
off or go right through the cyclodextrin
molecule.
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CAPTURE TECHNOLOGY
HEAT
Capture technology is a development from Milliken, a company that has been making and treating
fabrics since 1865. Over the years and through international manufacturing, Milliken has gained over
2,200 patents and has the largest textile (fabric) research center in the world. Capture technology
was designed as a home care technology to clean and control odors in carpets and furniture. More
recently, it has been applied to clothing fabric to absorb human odor as well.
The way Capture technology works for controlling odor is a polymer with a bunch of little branches,
similar to the shape of a dandelion, is bound to a fabrics surface. When someone is wearing fabric
with the Capture technology, the odor molecules their body releases is intended to be absorbed by
the little dandelion structures. Once the odor molecules are absorbed by the Capture technology
the odor molecules stick to the structures. To clean the fabric and empty the dandelion structures,
put the fabric through a regular washing cycle and the odor molecules are released and the fabric
is clean and ready to be used again.
The main advantage to using Capture technology is that it can be maintained with regular washing
cycles and no special treatment needs to be used on the fabric. Also, the dandelion like structures
that absorb the odor can be designed to absorb a specific odor. The negatives are that they
are usually only effective for a limited time and cannot adsorb the quantity of odors carbon can.
The clothing company Under Armor uses Capture in some of their clothing fabrics and says the
technology is effective for over 25 washings, where carbon based odor control technologies can be
reused considerably longer.
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CAPTURE TECHNOLOGY
Capture uses a polymer with little branches
bound to the fabric. As odor passes through
some molecules stick to branches reducing
odor.
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ENZYMES
HEAT
The best way to explain enzymes is they are a type of protein structure that are made by cells and
found in all living things. It is important to also understand that different enzymes serve different
functions. They are in saliva to break food down into sugars for the body to use, they are used in
clothing to remove ultraviolet glow, they are used in liquids and sprays to breakdown odor molecules
and more.
CHEMICALLY ALTERED
MOLECULES
Basically there are six different classes of enzymes. However, within these six classifications there
are around 10,000 different kinds of enzymes that all break down different kinds of molecules
changing their chemical functions in one way or another. All of the six main classes of enzymes have
a different reaction to the way they change cells and molecules. Once you determine what and how
you want to change, the right enzymes with the right environmental conditions have to be found to
reach the results you are looking for. Their main purpose is to change the cells and molecules so
they do different things and have different functions than they previously did. Enzymes treat odor
molecules the same way. The enzymes act as a mechanism that changes the chemical makeup
of odor molecules, meaning that the change that occurs inside these odor molecules prevents
bacteria causing odors from growing.
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One of the downfalls to enzymes is that the environment can influence their effectiveness.
Temperatures that are too extreme or other varying environmental conditions can affect the way the
enzymes change the odor molecules resulting in the enzymes being ineffective in killing the odor
causing bacteria. Another issue faced with using enzymes for odor control is that they generally
have a short life. Usually enzymes are used in a liquid form and because the life of the enzymes is
limited they need to be reapplied to the fabric often, which can become expensive.
ENZYME TECHNOLOGY
Enzymes can change the chemical makeup of odor molecules, meaning that the
change inside these molecules prevents
bacteria causing odors from growing.
Some of the benefits of enzymes are they are strong for the time they are active. Another benefit is
there are many, many different kinds of enzymes that can be applied to carry out a specific action.
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