Ingredients
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Surfactants and builders are the major components of cleaning products.
Other
ingredients are added to provide a variety of functions, such as increasing
cleaning performance for specific soils/surfaces, ensuring product
stability and
supplying a unique identity to a product. Let's examine how surfactants and
builders work and then review other commonly used ingredients.
Surfactants
Surfactants, also called surface active agents, are organic
chemicals that change the properties of water (see Chemistry.)
By lowering the surface tension of water, surfactants
enable the cleaning solution to wet a surface (e.g., clothes,
dishes, countertops) more quickly, so soil can be readily
loosened and removed (usually with
the aid of mechanical action).
Surfactants also emulsify oily soils
and keep them dispersed and
suspended so they do not settle back
on the surface. To accomplish their
intended jobs effectively, many cleaning
products
include two or more surfactants.
Surfactants are generally classified by their ionic (electrical charge)
properties in water.
Anionic surfactants are used in
laundry
and hand dishwashing detergents;
household cleaners; and personal
cleansing products. They ionize (are
converted to electrically charged
particles) in solution, carry a negative
charge, have excellent cleaning
properties and generally are high
sudsing. Linear alkylbenzene sulfonate,
alcohol ethoxysulfates, alkyl sulfates
and soap are the most common anionic
surfactants.
Nonionic surfactants are low sudsing and are typically
used in laundry and automatic dishwasher detergents
and rinse aids. Because they do not ionize in solution
and thus have no electrical charge, they are resistant to
water hardness and clean well on most soils. The most
widely used are alcohol ethoxylates.
Cationic surfactants are used in fabric softeners and
in fabric-softening laundry detergents. Other cationics
are the disinfecting/sanitizing ingredient in some
household cleaners. They ionize in solution and have a
positive charge. Quaternary ammonium compounds are
the principal cationics.
Amphoteric surfactants are used in personal cleansing
and household cleaning products for their mildness,
sudsing and stability. They have the ability to be anionic
(negatively charged), cationic (positively charged) or
nonionic (no charge) in solution, depending on the pH
(acidity or alkalinity) of the water. Imidazolines and
betaines are the major amphoterics.
Builders
Builders enhance or maintain
the cleaning efficiency of the
surfactant. The primary
function of builders is to
reduce water hardness.
This is done either by
sequestration or chelation
(holding hardness minerals in
solution),
by
precipitation
(forming an insoluble
substance), or by ion
exchange (trading electrically charged particles). Complex
phosphates and
sodium citrate are common sequestering builders. Sodium carbonate and
sodium silicate are precipitating builders. Sodium aluminosilicate
(zeolite) is an
ion
exchange builder.
Builders can also supply and
maintain alkalinity, which assists
cleaning, especially of acid soils;
help keep removed soil from
redepositing during washing;
and
emulsify oily and greasy
soils.
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