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Handbook of Solvents - George Wypych - ChemTech - Ventech!

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14.7 Dry cleaning 883<br />

14.7 DRY CLEANING - TREATMENT OF TEXTILES IN SOLVENTS<br />

Kaspar D. Hasenclever<br />

Kreussler & Co.GmbH, Wiesbaden, Germany<br />

Most processes in manufacturing and finishing <strong>of</strong> textiles are aqueous. In order to prevent<br />

water pollution, some years ago developments were made to transform dyeing-, cleaningand<br />

finishing-processes from water to solvents. During 1970-1980 solvent processes for<br />

degreasing, milling, dyeing and waterpro<strong>of</strong>ing <strong>of</strong> textiles could get limited economic importance.<br />

All these processes were done with tetrachloroethylene (TCE). After getting<br />

knowledge about the quality <strong>of</strong> TCE penetrating solid floors, stone and ground, contaminating<br />

groundwater, this technology was stopped.<br />

Today the main importance <strong>of</strong> solvents in connection with textiles is given to dry<br />

cleaning, spotting and some special textile finishing processes.<br />

14.7.1 DRY CLEANING<br />

14.7.1.1 History <strong>of</strong> dry cleaning<br />

Development <strong>of</strong> dry cleaning solvents<br />

The exact date <strong>of</strong> discovery <strong>of</strong> dry cleaning is not known. An anecdote tells us that in about<br />

1820 in Paris, a lamp filled with turpentine fell down by accident and wetted a textile. After<br />

the turpentine was vaporized, the wetted areas <strong>of</strong> the textile were clean, because the turpentine<br />

dissolved oily and greasy stains from it.<br />

In 1825, Jolly Belin founded the first commercial “dry laundry” in Paris. He soaked<br />

textile apparel in a wooden tub filled with turpentine, cleaned them by manual mechanical<br />

action, and dried them by evaporating the turpentine in the air.<br />

After getting the know-how to distill benzene from tar <strong>of</strong> hard coal in 1849, this was<br />

used as a solvent for dry cleaning because <strong>of</strong> its far better cleaning power. But benzene is a<br />

strong poison, so it was changed some decades later to petrol, which is explosive. In order to<br />

reduce this risk, petrol as dry cleaning solvent was changed to white spirit (USA: Stoddard<br />

solvent) with a flash point <strong>of</strong> 40 - 60°C (100 - 140°F) in 1925.<br />

The flammability <strong>of</strong> the hydrocarbon solvents in dry cleaning plants was judged to be<br />

risky because <strong>of</strong> fire accidents. After finding the technology for producing inflammable<br />

chlorinated hydrocarbons, trichloroethane and tetrachloroethylene (TCE) were introduced<br />

in dry cleaning since about 1925. These solvents gave the opportunity for good cleaning results<br />

and economic handling. Up to 1980, TCE was the most important solvent for dry<br />

cleaning worldwide.<br />

Compared to TCE, fluorinated chlorinated hydrocarbons (CFC) <strong>of</strong>fer benefits to dry<br />

cleaning because <strong>of</strong> their lower boiling points and their more gentle action to dyestuffs and<br />

fabrics. So since 1960 these solvents have had some importance in North America, Western<br />

Europe, and the Far East. They were banned because <strong>of</strong> their influence on the ozone layer in<br />

the stratosphere by the UNESCO’s Montreal Protocol in 1985.<br />

At the same time, TCE was classified as a contaminant to groundwater and as a dangerous<br />

chemical to human health with the possible potential <strong>of</strong> cancerogenic properties. As<br />

a result <strong>of</strong> this, hydrocarbon solvents on the basis <strong>of</strong> isoparaffins with a flash point higher

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