Let’s get back to
drycleaning basics
Today, there are many new operators
without the hard core experience required to cope with the
highly technical aspects of drycleaning. These operators, some
of whom are graduates of general courses, are being placed at
the mercy of their “seasoned” cleaners/spotters
who, themselves, are without the technical and scientific
knowledge required in this industry.
 | ||
When asked a simple, basic question about
the drycleaning process, I answer by the question:
“Didn’t you learn about that in school”? The
reply is: “Yes, but I forgot, and I would have to refer
to my notes for the answer.”
The real answer is found in hands-on
experience — on the job training in the actual operation
of the machinery, but with the instructor continually reminding
the student how he/she is applying the lectured science to the
job at hand.
This is only the beginning, however, and
the new operator must continue his/her practice in the new
business just purchased or founded from the “ground
up.”
This article will explain the composition
and types of soil, and its method of removal.
The soiling of fabrics is considered as
either overall soiling or localized soiling. Overall soiling is
a smudging throughout the fabric, whereas localized soiling
occurs on small areas of the fabrics and usually connotes a
specific kind of soil. An example of localized soiling is a
food stain on the sleeve of a dress.
The purpose of drycleaning is to remove
soil from the fabric without damage to its yarns or dye and to
leave the fabric with the same size, shape and hand as when it
was manufactured. This is accomplished by the absence of
swelling of the fibers/yarns. This is the difference between
the use of dry solvent and wet water. The water will swell the
fibers/yarns whereas the dry solvent will not. Actually,
drycleaning is more of a surface cleaner while wetcleaning is
more thorough.
This is the reason for creases not being
removed in drycleaning but completely removed in wetcleaning
(unless permanently creased). This phenomenon is explained
later in this article under “Wetting vs.
Swelling.”
The effect of soil on a fabric
Overall soiling makes a garment
unattractive since the colors are dulled, patterns are
obscured, dark areas form, and it becomes virtually unusable if
there is extensive overall and/or localized soiling.
Salt found in perspiration and food may
cause the fabric to stiffen. Salt can also cause physical
fabric damage in silk yarns. Some dyes on wool fabrics change
color from contact with salt or a salt solution.
Starches and proteins in food attract
insects to the stained area of fabrics. Insects are more apt to
attack a soiled fabric than a clean one.
Most soils are either acid or alkaline in
nature. Acids or alkalis can cause physical damage to fabric,
color change, or both. For these reasons, it is important to
know what kind of soil is in a fabric and to remove it as soon
as possible.
Most people are familiar with the three
states of matter: gas, liquid and solid. Since solid matter
concerns cleaners, we shall discuss matter only with respect to
its solid state. There are two distinct classes of solids and a
third class that combines the features of the other two.
One class consists only of ions, which are
electrically charged atoms. They are either positively charged
(called “cations”) or negatively charged (called
“anions”). For example: salt is a solid whereby the
salt crystal is held together because of the electrical
attraction between the cations and anions.
The other class of solids consists of
simple molecules made of uncharged atoms. These molecules
contain no ions and are, therefore, “non-ionic” and
electrically inert. For example: paraffin wax, which has its
molecules held together in a solid structure by a gravitational
bond.
Solids that contain ions have a great
attraction for water and are called “hydrophilic.”
These solids are usually water-soluble, never oil-soluble (dry
solvent). Solids that contain no ions or other water attracting
groups, such as paraffin wax, are generally oil-soluble but
never water-soluble. In fact, they resist even being wetted by
water and are, therefor, called “hydrophobic.”
The third class is composed of solids that
are “non-ionic” yet “hydrophilic.” This
happens because the molecules contain certain non-ionic
structural units that can absorb water.
Simple alcohols are typical of this type
and are classed within the “hydroxl group.” This
consists simply of an oxygen and hydrogen atom linked to each
other and to the balance of the molecule.
The hydroxl group makes the alcohol
molecule water-soluble despite the balance of the molecule
being “hydrophobic.” This results from part of the
molecule containing oxygen to make it “hydrophilic”
and another part of the molecule that contains no oxygen to
retain its hydrophobic nature. For this reason, alcohols,
organic acids and amines are frequently both water-soluble and
oil-soluble.
Wetting vs. swelling
In one soaking process, the bonds between
the molecules of the liquid are broken, but bonds between the
molecules of the solid are unaffected. The result is that the
liquid molecules adhere to the surface of the solid for partial
solubility. This process is called “wetting.”
In the other soaking process, wetting
occurs; but the bonds of the solid are weakened and the liquid
molecules penetrate into the solid to some extent, but not
enough to cause solution. This process is called
“swelling.”
Both water and dry solvents will
“wet” all of the common textile fibers, but only
water will “swell” any of them. Swelling is the
cause of water’s adverse effect on the finish of the
“hydrophilic” fibers.
This is, of course, the major distinction
between drycleaning solvents and wetcleaning with water and
detergent. The perfect cleaning agent is one that will dissolve
the soil but only wet the fibers.
The problem with swelling of fibers has
somewhat been solved recently with the development of additives
and conditioners, by fabric manufacturers, to make fabrics
somewhat resistant to the swelling of its fibers. Also, there
have been additives developed by chemical suppliers which have
the effect of reducing the danger of fiber swelling during the
wetcleaning process.
However, wetcleaning of soft, loosely
woven and knitted animal fibers (wool, angora, cashmere,
vicuna, etc.) is still not the desired process over traditional
drycleaning. We must remember that there are three conditions
for shrinkage of animal fibers: heat, mechanical action and
water. It takes two of these conditions to get shrinkage with
mechanical action being one of the two.
Therefore, if we eliminate the element of
mechanical action the fabric should not shrink, but if the
fabric has been conditioned against “fiber
swelling” the wetcleaning process should be relatively
safe. “Relatively safe” means that there can always
be the slight possibility that the wetcleaning process, with
conditioners, could still give negative results. However, as
testing with chemicals progresses, the risk of swelling becomes
more safe in the future.
The perfect cleaning agent, however,
behaves as desired toward many soils, but, unfortunately, not
toward all. We need, therefore, to understand the distinction
between various soils. An infinite number of soils and stains
can contact a fabric in wear and use.
Types of soil
Soils may be classified into four major
groups. This makes it much simpler to discuss soil. Instead of
trying to find out the exact nature of each staining material,
we need only find out what type, or types, of soil are present
in the fabric.
For example, there are many different oils
and greases that may soil a fabric. We do not have to know the
exact name of each grease or oil. We merely need to know that
the soil is an oil or grease. We will learn how to remove this
type of soil later.
Solvent-soluble soil
Solvent-soluble soil is soil that is
dissolved by drycleaning solvent. Examples of solvent-soluble
soil are mineral oils, lubricating oils (mineral), greases
(mineral), waxes and silicones.
Animal fats and vegetable oils, which are
not oxidized, are soluble in perchloroethylene dry solvent due
to its very high KBV (measurement of oil and grease
solubility). Petroleum, hydrocarbon and most alternative
solvents (except glycols) will not dissolve animal fat and
vegetable oil.
Water-soluble soil
Water-soluble soils may be divided into
two groups:
1. Stains which are completely soluble in
water.
2. Stains which are partially soluble in
water.
Neither of the two groups are soluble in
drycleaning solvent.
Examples of stains completely soluble in
water are table sugar (cane sugar) and salt. These stains are
found in many substances, such as perspiration, foods and
beverages.
Partially water-soluble stains are
referred to as “built up” food stains since they do
not penetrate the fabric completely but lay on the surface.
Examples of these stains are soups, catsup, mustard and most
solid foods.
Insoluble soil
Insoluble soils are not dissolved by
drycleaning solvents, water or any other special solvents.
Examples of insoluble soil are small particles of lint, dust,
carbon, sand, earth, clay and cement. Removal of these soils is
by flushing action of any solvent, mechanical action in the
load, detergent action to help release the soil and solvent
flow rate through the filter and back to the machine’s
cylinder.
Re-deposition of soil, commonly referred
to as “graying” of fabrics, is often caused by fine
particles of insoluble soil settling back on the fabric during
the drycleaning process.
These fine particles can be re-deposited
initially within the machine’s cylinder during a pre-wash
cycle or after they have passed through the filter and returned
to the cylinder due to the much smaller size of the soil
particle than the size of openings within the filter medium
(paper, fabric or metal).
If this re-deposited soil is mixed with
activated carbon from the cartridge filter or powder carbon
pre-coat, the result is a stain which is almost impossible to
remove, especially from white garments.
Since most filter mediums are 30-35
microns, and diatomaceous earth filter powder is rarely used
any longer as a filter coating for mediums of 60+ microns,
filtering of insoluble soils is improved after some of the
insoluble soil has been deposited onto the (powderless) filter
medium.
The best filtration is by use of
diatomaceous earth since that product, evenly distributed onto
the 60+ micron filter medium, is porous to liquids but
non-porous to solid soils. However, the filter powder adds to
the cost of filtration and to hazardous waste removal for
perchloroethylene solvent and petroleum solvents with flash
points below 140° F.
Chemically-soluble soil and removal by
special agents
This class of soil is not soluble in
drycleaning solvent or water. These soils are either
completely, or partially, soluble in special solvents or
chemical agents.
Examples of these soils are nail polish,
plastic adhesives, inks, paint, enamel, lacquer, rust,
permanent dyes, oxidized oil and caramelized sugar. Some
protein (food and albumin) stains require digestive action
using enzymes or bleaching action. This class requires
considerable time for removal since most of the work is done by
hand on the individual stain in the spotting department.
Factors affecting removal of soil
1. Extent of soiling: The extent of
soiling is simply how much soil is in the fabric and how deeply
it is embedded. The more soil there is in the fabrics, the more
difficult it is to remove.
Examples of where soil may be heavily
embedded are the hemlines of dresses and coats; bottoms of
pants and coat sleeves; necklines of dresses, coats and shirts;
and areas of excessive wear and exposure to soils.
2. Length of time the soil has been in the
fabric: Some soils and stains become more difficult to remove
when they have been in the fabric for a long period of time,
and they become “set” with age.
Examples of these “set” soils
and stains are oxidizing oils, paints, enamel, varnishes, blood
and caramelized beverage (reducing sugar). These soils and
stains are relatively easy to remove when they are fresh, but
they become more difficult to remove as they age and are almost
impossible to remove when they have completely cured or
“set.” Examples of oxidizing oils are tung, caster
and most vegetable oils.
3. Type of soil: If the soiling matter is
composed of only solvent-soluble soil, it may be removed easily
by the drycleaning process. Water-soluble soil requires the use
of water which is basically not contained in the drycleaning
solvent. It must be removed either by safely introducing water
into the drycleaning bath or by hand on the spotting board.
Insoluble soil presents more problems as
previously noted in “Insoluble Soil” above. Graying
may occur when a large amount of this soil is not completely
filtered causing re-deposition of soil and dyes.
4. Type of fabric: Fabrics differ in fiber
content and fabric construction as well as the type of dye and
finishing agent used to impart “hand” and drape.
The type of fabric is a very important factor in soil removal.
Also, a single garment may be composed of several entirely
different fibers and yarns, each of which can present different
problems in the cleaning process.
Different fibers, dyes and finishes do not
all behave the same way in drycleaning. Some require special
handling to avoid damage. One part of the garment may contain a
fabric which is solvent-soluble, or the plastic trim may become
stiff because the plasticizer used in manufacture to impart
suppleness to the plastic material dissolves.
Fabric construction also determines how
well soil may be removed. Tightly woven fabrics well hold
insoluble soil particles more tightly than will loosely woven
fabrics. And, consequently, soil removal is more difficult.
Knowing the type of soil and the methods
that will remove it in drycleaning are not enough. We must also
know how the fabric will behave in drycleaning.
How soil is removed
The removal of soil can be accomplished in
several ways and by various methods.
1. Removal of soil by drycleaning solvents:
We have seen that drycleaning solvent alone will remove a
great deal of soils, but drycleaning solvent alone will not do
a very good job of total soil removal. Drycleaning solvent is
aided by the use of surfactant detergents. There are methods
that enable us to use water with drycleaning solvent to remove
some of the water-soluble soil in the drycleaning machine.
2. Removal of soil by wetcleaning: Fabrics
badly soiled with water-soluble stains may require wetcleaning
as being more practical in place of hand removal of those
stains on the spotting board. Also, the type of fiber content
or the solvent-solubility of the dye may require the
wetcleaning process in the place of drycleaning.
Simply described, the wetcleaning process
consists of water, water-soluble detergent and various agents
formulated to condition the fabrics against any dangers of the
wetcleaning process, especially if the fabric is of the
animal-type or water-sensitive synthetic base. Wetcleaning can
also remove general overall soiling, including insoluble soil.
Presently, our industry is becoming more
prone to read, and follow, all care labels. This means that
garments with care labels prescribing only “washing
methods” should be professionally wetcleaned in the place
of drycleaning, even if the garment can be successfully
drycleaned alternatively.
By not adhering to the care label attached
to the garment, the cleaner is legally liable for any damage
sustained by the alternate process; but if the care label is
followed with proper procedures, the cleaner is not legally
liable for any damage sustained by that process.
3. Removal of soil by physical methods: In
the use of solvents, some soils are actually dissolved, but in
the removal of soil by physical means nothing is dissolved.
To better understand physical removal of
soil, let us look at some examples. Brushing lint from a fabric
is removing soil by physical means. Brushing the neck of a
heavily-soiled coat or shirt with pre-spotting solution in
order to break-up body oil and perspiration is removing soil by
physical means.
Removing blood or glue on the spotting
board is removing soil by physical means since the removal of
these stains requires some hand mechanical action.
Next month we will discuss the actual
removal of each type of soil in the dryclean process by
describing all the elements required.
Note: My spotting video. “The Caplan
Method of Stain Removal,” which includes my comprehensive
text (edited by Hal Horning) and the handy spotting board
reference, is available in English, Korean (video only) and
Spanish (video only) from the Golomb Group, c/o Dennis McCrory,
7664 Plaza Court, Willowbrook, IL 60521, phone (800) 679-5856.
This video is actually a “Trainer in a Box,” and is
a complete training course for both experienced and novice
spotters. My comprehensive text reinforces all of the
background technical material required to produce a
professional spotter. Each method of spot removal is thoroughly
discussed and demonstrated. Bleaching and use of digesters are
explained in addition to basic textile chemistry.
Also available from the Golomb Group, in
English and Spanish, is my video on step-by-step shirt
finishing which includes my comprehensive text in loose-leaf
form (English only) outlining each procedure for
single-operator and two-operator cabinet shirt units. Both
units are demonstrated using a cabinet sleever and single, or
triple, heated collar former. This procedure was developed by
me for top quality with no touch-up (regular sizes) together
with maximum production without overexertion by its operators.
Avoiding shrinkage, wilting and dipping of the collar, together
with its proper “breaking and forming” on the
heated collar former, are all demonstrated. Both the collar and
front buttonhole placket, the two thickest parts of the shirt,
are totally dried under the press head with no loss of
production. Attractive detailing and packaging of the hangered
shirt, padding, steam pressure and timing are all discussed. A
unique wash formula to give whiter whites, brighter colors and
complete removal of grease and body oils is included in the
loose-leaf text book.
Stan Caplan has over 35 years experience
in his own high volume dry-cleaning, laundry and tailoring
plant and two package plants with adjoining coin-operated
laundry and dry-cleaning. He is a former chief instructor at
the International Fabricare Institute, The Southwest
Drycleaners Association School, the Illinois State Fabricare
School, the Michigan Institute of Laundering and Dry-cleaning
School, the Mississippi Fabricare Association School and
Louisiana Fabricare Association School, the Pennsylvania
Drycleaners and Launderers Association School (now
Pennsylvania-Delaware Cleaners Association), the Johannesburg
Cleaners Association School (South Africa), the Hyatt-Regency
Southeast Asia School (Singapore and Hong Kong) and numerous
short courses in all areas of the fabric care industry
throughout the US and Canada. Stan offers consulting, training
and engineering services in all areas of the fabric care
industry from customer service area to the boiler room. His
total system (TQM) encompasses maximum efficiency, economy and
product excellent quality. Stan can be reached at 3601 Clarks
Lane, Suite 307, Baltimore, MD 21215, phone/fax (410) 358-0870.;
his e-mail address is:
stancap100@aol.com.
