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FACTS ABOUT LAUNDRY
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TYPES OF LAUNDRY PRODUCTS ... Continued
Detergent Ingredients
Whatever their form or their sudsing
characteristics, laundry detergents
must perform the same basic functions, but diversity exists among
laundry detergent formulas. They
may contain similar ingredients, but
each ingredient is in the formula at a
specified amount for a particular
purpose.
SURFACTANT
The surfactant or surface active
agent is perhaps the most important
ingredient present in every synthetic
detergent formulation. The surfactant:
1) improves the wetting ability of
water;
2) loosens and removes soil with the
aid of wash action;
3) emulsifies, solubilizes or suspends
soils in the wash solution.
Surfactants are organic compounds
consisting of two parts: a water-loving
(hydrophilic) portion and a water-hating (hydrophobic) portion. The
water-hating ends attach themselves
to the soil particles present in or on
the fabrics being washed, while the
water-loving ends are attracted to
the water. The surfactant molecules
surround the soil particles, break them
up and force them away from the
surface of the fabric, then suspend
the soil particles in the wash water.
Detergents may contain more than
one kind of surfactant. These surfactants differ in their ability to remove
certain types of soil, in their effectiveness on different fabrics and in their
response to water hardness. Surfactants are classified by their ionic
(electrical charge) properties in the
water. The following major categories
are used in laundry products:
Anionic Surfactants
Anionic surfactants are the most
widely used. In water, their hydrophilic
portion carries a negative charge,
which can react in the wash water
with the positively charged water
hardness (calcium and magnesium)
ions that tend to deactivate them.
These surfactants are particularly
effective at oily soil cleaning and
clay soil suspension. But, to different
degrees (depending on their chemical structure), they need help from
other ingredients to prevent partial
inactivation by water hardness ions.
Nonionic Surfactants
Nonionic surfactants do not ionize in
solution. Lack of charge enables
them to avoid water hardness
deactivation. They are especially
good at removing oily type soils by
solubilization and emulsification.
Nonionic surfactants are frequently
used in some low sudsing detergent
powders and in general purpose liquid
detergents. Nonionics may be mixed
with anionics in some powder or
liquid detergents.
Cationic Surfactants
Cationic surfactants carry a positive
charge in water and do not react
with positively charged water
hardness ions. Cationics are used in
fabric softeners and in a few combination fabric-conditioning detergents. In a properly balanced
combination with nonionics, detergency is achieved while depositing
enough cationic surfactant on
fabrics to produce softening and
antistatic benefits.
The surfactants in today's household
laundry detergents manufactured for
use throughout the United States are
biodegradable and have been since
mid-1965.
BUILDER
The builder is the second most
important ingredient in a detergent
formula because it enhances or
"builds" the cleaning efficiency of the
surfactant by inactivating water
hardness minerals.
Builders provide one or more of
the following functions:
- Soften water by tying up water
hardness
- Help prevent water hardness
ions from interacting with negatively charged surfactants so
surfactants can concentrate
on soil removal
- Increase the efficiency of the
surfactant system
- Most provide a desirable level of
alkalinity, which aids cleaning
- Most disperse and suspend soils
and prevent their redeposition
Builders are used in
general purpose laundry powders and liquids
but not in light duty detergents
(powders or liquids). Most
general purpose liquids contain builders such as
citrate, but some
are unbuilt. The unbuilt liquids use
surfactants which are less hardness
sensitive, instead of including a
builder to minimize interactions with
water hardness minerals. The general purpose liquids should not be confused
with light duty liquids, which are
designed primarily for washing dishes
by hand.
Builders soften water by sequestration, precipitation or ion exchange.
Sequestering Builders
Sequestering builders, such as
polyphosphates, inactivate water
hardness mineral ions and hold them
tightly in solution. Another builder,
citrate, while not as strong a
sequestrant as phosphate, contributes
to detergency performance in some
types of heavy duty liquid detergents.
Precipitating Builders
A precipitating builder, such as
sodium carbonate or sodium silicate,
removes water hardness ions by a
nonreversible reaction, forming an
insoluble substance or precipitant.
They are especially effective on
calcium ions.
Ion Exchange Builders
An ion exchange builder, such as
aluminosilicate (zeolite), is an insoluble
material which ties up calcium
hardness minerals.
ADDITIONAL INGREDIENTS
Antiredeposition Agents
Antiredeposition agents may be
made from complex cellulosic
materials such as carboxymethylcellulose (CMC), or synthetic materials
such as polyethylene glycol and
polyacrylates. They aid in preventing
loosened soil from redepositing onto
cleaned fabrics. Polyphosphate
builders also help in reducing
redeposition.
Light duty liquids designed for hand
dishwashing do not contain
antiredeposition agents.
Corrosion Inhibitor
Corrosion inhibitor, usually sodium
silicate, helps protect washer parts
from corrosion.
Light duty liquids designed for hand
dishwashing do not contain corrosion
inhibitors as they are not intended for
use in a washing machine.
Fluorescent Whitening Agents
Fluorescent whitening agents (FWAs
or brighteners) are complex organic
molecules which adhere to fabrics as
though they were dyes. Ultraviolet
energy is absorbed, converted and
emitted as visible blue light to
enhance fabric appearance and
maintain whiteness or brightness.
The light duty liquids designed for
hand dishwashing do not contain
FWAs.
Processing Aids
Processing aids cover a considerable
list of ingredients such as sodium
sulfate, water, solvents like alcohol, or
xylene sulfonate. They provide the
product with the right physical
properties for its intended use.
Sodium sulfate, for example, helps
provide crisp, free-flowing
powders. Alcohols are often used in liquid
products where they serve as solvents for the detergent ingredients,
adjust the viscosity and prevent
product separation. Since the water
content of liquids is fairly high,
alcohols also provide protection to
the product under extremely cold
storage conditions by lowering the
freezing point.
Colorants
Colorants are added to lend an
individuality to the product or
dramatize a special additive contributing to product performance.
Additionally, blue colorants may
provide a bluing which imparts a
desirable blue/white color to white
fabrics.
Fragrances
Fragrances provide three functions,
regardless of the scent used. They
cover the chemical odor of the
detergent and the odor of soils in the
washing solution. Plus, they impart a
pleasant scent to fabrics, thus
reinforcing the clean performance.
Additionally, a fragrance contributes
to the character of the product.
Some detergents are offered in
unscented versions, appealing to
consumers who prefer low or no
scent on laundry. They may also
appeal to people whose skin is
sensitive to fragrance ingredients.
Opacifiers
Opacifiers are used in some liquid
products to provide a rich, creamy,
opaque appearance.
Oxygen Bleach
Oxygen bleach provides the detergent with an all-fabric bleaching
action for stain and soil removal. The
most common agent used is sodium
perborate tetrahydrate, but sodium
percarbonate can be used.
Recently, activated bleach systems
have been introduced that provide
effective fabric whitening at today's
lower wash temperatures.
Enzymes
Enzymes aid in breaking down complex soils, especially proteins such as
grass and blood, so that these soils
can be more easily removed by
other detergent ingredients.
Suds Control Agents
Suds control agents are used as suds
stabilizers or suppressors. Suds stabilizers are limited to detergents, such as
light duty products, where lasting,
voluminous suds are desirable. Suds
suppressors inhibit sudsing or control it
at a low level. Special long chain
soaps are one class of compound
used to control sudsing in powder
and liquid laundry detergents.
Fabric Softening Agents
Fabric softening agents impart
softness and control static electricity
in fabrics. Cationic surfactants (e.g.,
quaternary ammonium compounds)
are commonly used.
Other Ingredients
Other ingredients may be added to
a laundry detergent system to
provide specialized performance or
convenience.
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