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Enzymes
Most informative documentation can be found at Novozymes
Borax Na2B4O75H2O
Useful where buffering at a low pH is required, synergism of
detergents at a low pH, and where high alkalinity would cause skin irritation.
Sodium Chloride NaCl
Salt is used as a viscosity increasing agent in anionic detergent
solutions. Up to 10% salt can be added to a powder formulation and proves effective on
blood, and on woollen garments. It has a positive effect on detergency.
Magnesium Sulphate MgSO4
May be added to powdered detergents containing perborates, whereby it acts
as a stabiliser. Also, in conjunction with DDBSA, it produces magnesium DDBS, which is
synergistic with sodium DDBS.
Ammonia
Ammoniated liquid cleaners have been available for decades, and have
good cleaning properties.
Caustic Alkalis
Sodium hydroxide and potassium hydroxide, are the most alkaline
materials available. These two chemicals are mainly used in heavy industrial type
formulations, and used by mechanical means rather than application by hand. Caustic soda
(sodium hydroxide) is used extensively to neutralise DDBSA, and as a neutralising agent in
many inorganic reactions.
Sodium hydroxide in a pearl form, mixed with soda ash, sodium tripolyphosphate,
surfactant, has a useful purpose in the cleaning of farm dairy milking equipment.
Anti-Redeposition Agents
(CMC) Carboxy methyl cellulose.
These products are used to stop the redeposition of dirt particles onto
the cloth in the laundering process. CMC is most beneficial in he laundering of cotton. It
is of questionable value on wool and synthetic fibres.
CMC is made by taking cellulose, and reacting it with chlor-acetic-acid, and
then subsequently neutralised to the Sodium Salt.
Not all of the -OH units on the cellulose are displaced by a -CH2COOH group.
Approximately half the -OH groups are substituted.
About 10% of the “active matter” of a laundry detergent powder should
be the percentage added as CMC. This is normally 1-2% CMC. It is the carboxyl group which
attracts the dirt and holds it, stopping redeposition onto the cloth.
Optical Brighteners
These are an integral part of laundry products, whether laundry
powders or laundry liquids. They are a dyestuff which is absorbed by textile fibres, but
are not easily rinsed off. They have the property of converting invisible, ultra violet
light into visible light on the blue side of the spectrum. This reflection of more light
than normal, makes the clothes look brighter than they actually are. Any yellowishness on
the fibre is made to look whiter, as well as brighter.
Optical brighteners are usually derivatives of coumarin or stilbene, and may
have patents and trade secrets.
Chelating Agents
EDTA (Ethylene diamine tetra-acetic acid), and NTA (Nitrilo triacetic
acid) their action is to “lock up” polyvalent ions in their molecules and make
these ions undetectable and ineffective.
The bonding of the ion is to both the amino and carboxylic groups. As phosphates
are not very good at sequestering trivalent ions, then EDTA and NTA are used in laundering
formulations to chelate trivalent iron, thus preventing iron stains in laundering. They
also prevent, by chelation, ions from decomposing Sodium Percarbonate, or other
“persalts”.
Triethanolamine, is also excellent for the chelation of ferric ions, when used
in a 1-18% Sodium Hydroxide solution.
Hydrocarboxylic Acid
The principle members of this group is Gluconic Acid, Citric Acid,
Tartaric Acid. Gluconic Acid is a good all round chelating agent, especially in solutions
containing free caustic soda.
One gram of Gluconic Acid will sequestrate 325 mg of Calcium Carbonate in a 3%
caustic soda solution. It will also chelate ferric ion over the whole pH range. Citric
Acid will sequestrate ferric ion especially in the presence of ammonia. |
