Basic
Cleaning Requirements
As with all detailing tasks; surface preparation is the most
important step to achieving e a flawless finish. The final result can only be
as good as the surface it’s applied to; so surface preparation is of paramount
importance. Products will properly bond to a substrate and that will ensure it
works correctly, and has both durability and desired aesthetics
Three types of energy are required;
•
Chemical energy- provided by the synthetic cleaner
•
Kinetic (abrasion) energy provided by machine or hand
•
Thermal energy -provided by warm or hot water
Test cleaner on an inconspicuous area then allowing it to dry to
make sure the solution does not react with the surface, is the best way to
ensure there are no surprises as to its affect, but be cognizant that it may
not react in exactly the same way as a heavily soiled area or that has been
subjected to UV-B radiation (faded)
Providing the cleaning product selected is suitable, apply
several drops of the selected cleaning solution in an inconspicuous area and
rub gently with a clean, white micro fibre towel. Do not over wet. Use small
amounts of the product and blot frequently, do not rub or use too much
pressure. Do not use the product if it
adversely changes your fabric's colour or texture.
Cleaning products (with the exception of glass cleaners) should
be sprayed on to a folded 100% micro fibre cotton towel, do not spray any cleaning
product directly to the surface, as this
may cause ‘spot or streak’ clean patches on the surface
Water surface tension
Water is the liquid commonly used for
cleaning, has a property called surface tension. In the body of the water, each
molecule is surrounded and attracted by other water molecules. However, at the
surface, those molecules are surrounded by other water molecules only on the
water side. A tension is created as the water molecules at the surface are pulled
into the body of the water.
This tension causes water to bead up on surfaces
(glass, fabric), which slows wetting of the surface and inhibits the cleaning
process. You can see surface tension at work by placing a drop of water onto a
counter top. The drop will hold its shape and will not spread.
Surfactant
In the cleaning process, surface tension
must be reduced so water can spread and wet surfaces. Chemicals that are able
to do this effectively are called surface active agents, or surfactants. They
are said to make water "wetter."
Surfactants perform other important
functions in cleaning, such as loosening, emulsifying sink dishes (dispersing
in water) and holding soil in suspension until it can be rinsed away.
Surfactants can also provide alkalinity, which is useful in removing acidic
soils.
Surfactants are classified by their
ionic (electrical charge) properties in water: anionic (negative charge),
non-ionic (no charge), cationic (positive charge) and amphoteric (either
positive or negative charge).
Soap is an anionic surfactant. Other
anionic as well as non-ionic surfactants are the main ingredients in today's
detergents. Now let's look closer at the chemistry of surfactants.
Soaps
Soaps are water-soluble sodium or
potassium salts of fatty acids. Soaps are made from fats and oils, or their
fatty acids, by treating them chemically with a strong alkali.
First let's examine the composition of
fats, oils and alkalis; then we'll review the soap making process.
Fats and Oils
The fats and oils used in soap making
come from animal or plant sources. Each fat or oil is made up of a distinctive
mixture of several different triglycerides.
In a triglyceride molecule, three fatty
acid molecules are attached to one molecule of glycerine. There are many types
of triglycerides; each type consists of its own particular combination of fatty
acids.
Fatty acids are the components of fats
and oils that are used in making soap. They are weak acids composed of two
parts:
A carboxylic acid group consisting of
one hydrogen (H) atom, two oxygen (O) atoms, and one carbon (C) atom, plus a
hydrocarbon chain attached to the carboxylic acid group. Generally, it is made
up of a long straight chain of carbon (C) atoms each carrying two hydrogen (H)
atoms.
Alkali
An alkali is a soluble salt of an alkali
metal like sodium or potassium. Originally, the alkalis used in soap making
were obtained from the ashes of plants, but they are now made commercially.
Today, the term alkali describes a substance that chemically is a base (the
opposite of an acid) and that reacts with and neutralizes an acid.
The common alkalis used in soap making
are sodium hydroxide (NaOH), also called caustic soda; and potassium Chemhydroxide
(KOH), and also called caustic potash.
How Soaps are made
Saponification of fats and oils is the
most widely used soap making process. This method involves heating fats and
oils and reacting them with a liquid alkali to produce soap and water (neat
soap) plus glycerine.
The other major soap making process is
the neutralization of fatty acids with an alkali. Fats and oils are hydrolysed
(split) with a high-pressure steam to yield crude fatty acids and glycerine.
The fatty acids are then purified by distillation and neutralized with an
alkali to produce soap and water (neat soap).
When the alkali is sodium hydroxide, a
sodium soap is formed. Sodium soaps are "hard" soaps. When the alkali
is potassium hydroxide, a potassium soap is formed. Potassium soaps are softer
and are found in some liquid hand soaps and shaving creams.
The carboxylate end of the soap molecule
is attracted to water. It is called the hydrophilic (water-loving) 10Chemend.
The hydrocarbon chain is attracted to oil and grease and repelled by water. It
is known as the hydrophobic (water-hating) end.
How Water Hardness Affects Cleaning Action
Although soap is a good cleaning agent,
its effectiveness is reduced when used in hard water. Hardness in water is
caused by the presence of mineral salts - mostly those of calcium (Ca) and
magnesium (Mg), but sometimes also iron (Fe) and manganese (Mn). The mineral
salts react with soap to form an insoluble precipitate known as soap film or
scum.
Soap film does not rinse away easily. It
tends to remain behind and produces visible deposits on clothing and makes
fabrics feel stiff. It also attaches to the insides of bathtubs, sinks and
washing machines.
Some soap is used up by reacting with
hard water minerals to form the film. This reduces the amount of soap available
for cleaning. Even when clothes are washed in soft water, some hardness minerals
are introduced by the soil on clothes. Soap molecules are not very versatile
and cannot be adapted to today's variety of fibres, washing temperatures and
water conditions.
Surfactants in Detergents
A detergent is an effective cleaning
product because it contains one or more surfactants. Because of their chemical
makeup, the surfactants used in detergents can be engineered to perform well
under a variety of conditions. Such surfactants are less sensitive than soap to
the hardness minerals in water and most will not form a film.
Detergent surfactants were developed in
response to a shortage of animal and vegetable fats and oils during World War I
and World War II. In addition, a substance that was resistant to hard water was
needed to make cleaning more effective. At that time, petroleum was found to be
a plentiful source for the manufacture of these surfactants. Today, detergent
surfactants are made from a variety of petrochemicals (derived from petroleum)
and/or oleo chemicals (derived from fats and oils).
Petrochemicals and Oleo chemicals
Like the fatty acids used in soap
making, both petroleum and fats and oils contain hydrocarbon chains that are
repelled by water but attracted to oil and grease in soils. These hydrocarbon
chain sources are used to make the water-hating end of the surfactant molecule.
Other Chemicals
Chemicals, such as sulphur trioxide,
sulphuric acid and ethylene oxide, are used to produce the water-loving end of
the surfactant molecule.
Alkalis
As in soap making, an alkali is used to
make detergent surfactants. Sodium and potassium hydroxide are the most common
alkalis.
How Detergent Surfactants Are Made
Anionic
Surfactants
The chemical reacts with hydrocarbons
derived from petroleum or fats and oils to produce new acids similar to fatty
acids.
A second reaction adds an alkali to the
new acids to produce one type of anionic surfactant molecule.
Non-ionic Surfactants
Non-ionic surfactant molecules are
produced by first converting the hydrocarbon to an alcohol and then reacting
the fatty alcohol with ethylene oxide. These non-ionic surfactants can be
reacted further with sulphur-containing acids to form another type of anionic
surfactant.
How Soaps and Detergents Work
These types of energy interact and
should be in proper balance. Let's look at how they work together.
Let's assume we have oily, greasy soil
on clothing. Water alone will not remove this soil. One important reason is
that oil and grease present in soil repel the water molecules.
Now let's add soap or detergent. The
surfactant's water-hating end is repelled by water but attracted to the oil in
the soil. At the same time, the water-loving end is attracted to the water
molecules.
These opposing forces loosen the soil
and suspend it in the water. Warm or hot water helps dissolve grease and oil in
soil. Washing machine agitation or hand rubbing helps pull the soil free.
Soaps & Detergents: Human Safety
As consumer needs and lifestyles change,
and as new manufacturing processes become available, the soap and detergent
industry responds with new products. A commitment to safety is a top priority
from the time a company begins working on a new product and continues as long
as the product is in the marketplace. Companies evaluate the safety of existing
cleaning products by talking with consumers, reviewing scientific developments
and monitoring product use data that may affect the safety assessment process.
To determine the safety of a cleaning
product ingredient, industry scientists evaluate the toxicity of the
ingredient. Toxicity is generally defined as any harmful effect of a chemical
on a living organism, i.e., a human, an animal, a plant or a microorganism.
Since all chemicals, including water (H2O), are toxic under certain conditions
of exposure, scientists must consider a number of factors affecting exposure.
These include the duration and frequency of exposure to the ingredient; the
concentration of the ingredient at the time of exposure; and the route and
manner in which the exposure occurs, e.g., eye, skin or ingestion. This information
is essential whether assessing the effect on humans, animals, plants or
microorganisms.
Because human safety and environmental
evaluations consider different types of exposures, they are evaluated by
different procedures. The principal steps in the assessment process are,
however, the same. They involve: assembling existing data on toxicity and
exposure; determining where new information is needed and, if necessary,
carrying out appropriate studies; and determining whether predicted exposure
levels are below levels that cause significant toxic effects.
This safety evaluation process enables
scientists to predict the potential risk, if any, associated with the use of
the ingredient or product, and determine if it is safe for consumers and the
environment.
Medical science has long confirmed the
important relationship between cleanliness and health. The regular use of
cleaning products is fundamental to the health of our society and the
well-being of its people.
Because cleaning products are part of
our everyday lives, it is essential that they not present a significant risk to
health. In considering the human safety of an individual ingredient or product,
toxicologists (scientists who assess the safety of a chemical) are concerned
with the effects from two types of exposures: intended and unintended. Intended
exposures occur with use of a cleaning product according to the manufacturer's
directions. Unintended exposures can result from misuse, through improper
storage or by accidental contact, such as when a liquid detergent is splashed
in the eye.
Hazards from these types of exposures
are evaluated from information obtained through (short-term) and chronic
(long-term) tests and through a review of existing data. Expected exposure
routes are considered as part of this evaluation.
Human safety evaluations begin with the
specific ingredients and then move on to the whole product. The effects for all
ingredients are considered as the product is formulated.
Toxicologists compare the expected
exposure to the expected effect during both product manufacture and use. How
will workers be exposed in the plant? What is the intended use of the product?
Is it to be diluted? Undiluted? Used daily in the home? Weekly in the
workplace? Toxicologists also consider the expected effect of an unintended
exposure. What is the potential hazard, for example, if a child drinks a
product directly from the bottle?
If this human safety evaluation
indicates an unacceptable risk, it may be possible to make the risk smaller by
changing the manufacturing process; reformulating to reduce or eliminate an
ingredient contributing to the toxic effect; or using labelling or a
child-resistant closure. If the risk cannot be reduced, the product will not be
marketed.
Even though manufacturers formulate
cleaning products to ensure that they are safe or 06sftyhave very low risk,
human health effects can still result from unintended exposure. To warn
consumers about a specific hazard, household cleaning products carry cautionary
labelling whenever necessary. For consumers, this is one of the most important
features of the label.
Federal regulations govern how
precautionary statements related to human safety are used on household cleaning
product labels. The regulations require that statements follow a standard
format. There is first a "signal word," followed by a short
description of the potential hazard. The following chart shows the signal words
- CAUTION or WARNING and DANGER - and what they mean:
POISON, which rarely appears on
household cleaning products, is the strongest indication of hazard and means
that accidental exposure could cause severe medical effects. The term may be
found on household lye and on some car care products, such as antifreeze.
Along with the safety evaluation process
and cautionary labelling, an extensive consumer education program on the proper
use, storage and disposal of cleaning products supports the human safety
efforts of the soap and detergent industry. In addition, the industry works
closely with poison control centre’s to assure that, should an accidental
exposure occur, treatment information is available to health care providers.
Together, these activities enable consumers to use cleaning products with
confidence in both their safety and performance.
Relevant Articles
- Basic Soap and Detergent Chemistry - http://togwt1980.blogspot.co.uk/2015/05/basic-soap-and-detergent-chemistry.html
- Using pH Values to Select Detailing Products - http://togwt1980.blogspot.co.uk/2015/04/using-ph-values-to-select-car-care.html
- Understanding Base (Alkalinity) - http://togwt1980.blogspot.co.uk/2015/05/understanding-alkalinity.html
I would like to think that these
articles become an asset to anyone who is new to detailing and to professionals
alike, as well as industry experts who seek to advance their knowledge.
I hope the above article was
informative. By having some understanding of the ‘What’ and ‘Why’ as well as
the ‘How’ along with a little science to help you understand how the chemicals
we use react, you can achieve the results you desire.
I would appreciate it if you would share this article
as it helps other detailers further their knowledge.
Questions and/ or constructive comments are always
appreciated.
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