Handbook of Solvents - George Wypych - ChemTech - Ventech!

14.7 Dry cleaning 893
14.7.3 TEXTILE FINISHING
The use of solvents for textile finishing has only some importance for the treatment of fully
fashioned articles. The processes are done in industrial dry cleaning machines. The advantages
are the same as in dry cleaning compared to washing: lower risk against shrinkage and
damage of sensitive garments.
14.7.3.1 Waterproofing
In Northern Europe, North America and Japan, some kinds of sportsware need to be waterproofed.
The treatment is done in dry cleaning machines with a load capacity larger than 30
kg(>60lbs). The machines need to be equipped with a special spraying unit, which allows
one to spray a solution of waterproofing agent into the cage of the machine.
The waterproofing agents consists of fluorocarbon resins dissolved in a mixture of
glycol ethers, hydrocarbon solvents and TCE. This solution is sprayed onto the garments,
which are brought into the cage of the machine. The spraying process needs about 5-10
min. After spraying, the solvent is vaporized in the same way as drying in dry cleaning, so
that the fluorocarbon resin will stay on the fibers of the garments. In order to get good results
and the highest possible permanence of water resistance, the resin needs to be thermally
fixed. In order to meet these requirements, a drying temperature of > 80°C (= 175°F) is necessary.
14.7.3.2 Milling
Solvent milling has some importance for the treatment of fully fashioned woolen knitwear.
The process is very similar to normal dry cleaning. The specific difference is the addition of
water together with the detergent, in order to force an exact degree of shrinkage and/or felting.
Milling agents are similar to dry cleaning detergent. They have specific emulsifying
behavior, but no cleaning efficiency. The process runs like this: textiles are loaded into the
machine, then solvent (TCE) is filled in before the milling agent diluted with water is added.
After this addition, the cage rotates for 10 - 20 min. The higher the water addition, the higher
the shrinkage; the longer the process time, the higher the felting. After this treatment, the
solvent is distilled and textile load is dried. High drying temperature causes a rather stiff
handle, low drying temperatures give more elastic handle.
14.7.3.3 Antistatic finishing
Antistatic finishing is used for fully fashioned knitwear - pullovers made from wool or mixtures
of wool and acrylic. The process is equal to dry cleaning. Instead of dry cleaning detergent,
the antistatic agent is added.
Antistatic agents for the treatment of wool consist of cationic surfactants such as
dialkyl-dimethylammonium chloride, imidazolidione or etherquats. Antistatic agents for
the treatment of acrylic fibers are based on phosphoric acid esters.