Handbook of Solvents - George Wypych - ChemTech - Ventech!

14.7 Dry cleaning 891
than in the adsorption systems, because there is no waste from adsorbing material. Disposal
costs are much lower than with adsorption.
14.7.2 SPOTTING
14.7.2.1 Spotting in dry cleaning
Spotting is the removal of stains from textiles during professional textile cleaning. Correct
cleaning, good lighting conditions, appropriate equipment, effective spotting agents, and
expert knowledge are indispensable.
Lighting conditions
Lighting of the spotting table with composite artificial light consisting of a bluish and a yellowish
fluorescent tube attached above the table approx. 80 cm from the standing point is
better suited than daylight. This ensures high-contrast, shadow-free lighting of the work
surface and allows for working without fatigue.
Equipment
Basic equipment should comprise a spotting table with vacuum facility, sleeve board, steam
and compressed air guns, and a spray gun for water. Spotting brushes should have soft bristles
for gentle treatment of textiles. Use brushes with bright bristles for bright textiles and
brushes with dark bristles for dark textiles. Use spatulas with rounded edges for removing
substantial staining.
14.7.2.2 Spotting agents
In dry cleaning, normally three groups of spotting agents are used:
Brushing agents
Brushing agents containing surfactants and glycol ethers dissolved in low viscosity mineral
oil and water. Brushing agents are used for pre-spotting to remove large stains from textiles.
They are applied undiluted with a soft brush or sprayed onto the heavily stained areas before
dry cleaning.
Special spotting agents
Special spotting agents are used for removing particular stains from textiles. The range consists
of three different products in order to cover a wide range of different stains. The products
are applied as drops directly from special spotting bottles onto the stain and are allowed
to react. The three products are:
• Acidic solution of citric acid, glycerol surfactants, alcohol and water for removing
stains originating from tannin, tanning agent, and fruit dye.
• Basic solution of ammonia, enzymes, surfactants, glycol ethers and water for
removing stains originating from blood, albumin, starch, and pigments.
• Neutral solution of esters, glycol ethers, hydrocarbon solvents and surfactants for
removing stains originating from paint, lacquer, resin, and adhesives.
Post-spotting agents
Stains that could not be removed during basic cleaning must be treated with post-spotting
agents. Most common is a range of six products, which are used in the same way, as the special
spotting agents:
• Alkaline spotting agent for stains originating from starch, albumin, blood, pigments
• Neutral spotting agent for stains originating from paint, lacquer, grease, and
make-up.
• Acidic spotting agent for stains originating from tannin, fruits, beverages, and rust.
• Acidic rust remover without hydrofluoric acid.