STAIN REMOVERS AND DETERGENTS
Once a textile material has been placed into service, it must be maintained
at an acceptable level. Serviceability or durability is the most important
characteristic of the fabrics used for apparel purposes. During daily use, the fabric
has to withstand considerable wear and tear due to washing (laundering), which
affects the serviceability. The effect of serviceability could be studied in terms of
change in several measurable fabric properties, such as strength, abrasion
resistance, etc. 1
There are many ways by which textiles become soiled in the home. Some
are unavoidable consequences of normal usage. The human body itself is a major
source of soiling on textile clothing, towels and other fabrics which come into
contact with it. Emulsions of blood, pus, urine, faeces, semen, vaginal secretions
and saliva together with dead skin cells and the output of sebaceous glands,
contribute proteins, lipids, inorganic electrolytes and simple compounds such as
urea to this soiling. Other causes are accidental and arise from contact with foods,
drinks, cosmetics, mud and the host of other materials encountered in daily life.
Of universal importance as a soil is sebum, a collection of lipids secreted
by the sebaceous glands. The detailed composition varies between races and sexes;
for an individual it varies with season, diet and state of health. At body
temperatures sebum forms a relative, mobile emulsion with water. It flows readily
from the skin and hair to the surface of the fabric fibres. Subsequent migration into
the fibres, together with ageing, makes it more difficult to remove. At the same
time, sebum binds particulate matter such as clays and metal oxides strongly to the
Some soils are commonly present on fabrics as spots or stains- highly
concentrated and highly visible. Their origins are diverse, and it is not possible to
make any generalizations about these forms of soiling. However, the following
diagram illustrates the types of material which give rise to the strong colours of a
selection of common stains.
Just as with sebum, ageing tends to make stains more difficult to remove.
e.g. the polyphenolics which give rise to the colour of many drinks undergo
oxidative polymerization reactions which increase the tenacity of the stain and can
also darken it.
The different soiling and ageing processes lead to 5 distinct categories of
textile soiling: - a) simple coatings b) mechanically entrapped particles c) semi-
liquid coatings d) colloidal deposits and e) molecular adsorption. From a) to e) the
categories are progressively more difficult to remove. Furthermore, soil may start
life at the level i.e. a simple coating, but through repeated washing will often reach
the final levels of colloidal deposits or molecular adsorbates.
The objective of laundering is to remove this complex mixture of materials
so that the article is fit to be used again. Not only is the appearance and feel of the
fabric restored, but washing also plays an important role in personal hygiene by
reducing the opportunity of growth of the bacteria and parasitic organisms. 2
WHAT IS A STAIN?
Stains are intensively coloured substances that cause noticeable soiling
even when present in small amounts on textiles and resist removal by detergents. 3
It is a collective term for the local discolouration of a textile which is
usually undesirable. Stains are caused by chemical bonding between a particular –
soil and the fibre which, in the strictest sense, is not representative of a typical
average soil removed by detergents in laundering. In contrast to such easily
removed soil, stains must either be decolourized or destroyed with the aid of
chemically active compounds. They are regarded as a form of localized soiling on
textile material. 4
The substance that causes stains generally falls into one of the following 3
Stains may be divided into 2 groups: the “build up” and the “absorbed‖.5
A built up stain is mostly on the surface, such as gum, food, blood, etc. The
absorbed stain penetrates into the material between the interlacings or the
interloopings of the yarns as well as actually ―getting into‖ the yarns of the goods.
The stains in the first group are easier to remove since simple methods are
employed, such as brushing, scraping, etc.
The absorbed stain must first of all be loosened from the material by
solvent action and then be taken out of the material by proper treatment. Some
absorbed stains do not respond to solvent action directly. These are treated with
chemicals which change the insoluble staining substance into soluble forms which
are then removed by the use of a solvent. In the use of bleach, the coloured
substances are converted to colourless compounds and in that way the stains are
Stain removal is easiest immediately after the fabrics have been subjected
to staining. It is important to know the kind of material that caused the stain and
the fibre of which the fabric is made.6
Removal of stains requires certain precautions to be observed. When the
origin of a stain is known, cleaning is simplified. Two factors that work against
ease of restoring the fabric are the length of time that the stain sets and heat the
spot may have experienced. The spot should be cleaned as fast as practical or kept
wet with water. Tumble drying should be avoided until the spot is removed.
It is important to remove the stain without changing the appearance or
changing the properties of the fabric. To accomplish this objective, it is
recommended to test the cleaning procedure on a small area of the garment.