Dry Cleaning
Dry cleaning is a process which removes dirt and stains from garments using a solvent other than water. As a profession, dry cleaning dates back to Mycenean civilization, around 1600 b.c. Archaeologists surmise that these ancient dry cleaners used absorbent earth or powdered meal to draw sweat, odors, and soil from clothing. Later innovations depended more on liquid solvents than on absorbent powders. In the seventeenth century, for instance, one adviser noted that turpentine would remove rosin by evaporating stains from the weave. Since the eighteenth century, people have protected fabrics from shrinkage and warpage by replacing water-based cleaners with chemical substitutes such as naphtha, benzine, and benzol. One technique involved the vigorous application of grated potatoes as a means of cleaning unwashable materials, furniture, and even oil paintings. Other products, such as pinene and camphene, successfully removed spots. A common home dry cleaning method called for the application of gasoline to dirty clothes to dissolve protein and fatty or oily substances, such as blood or gravy stains, but the flammability of gasoline proved hazardous.
In 1821, Thomas L. Jennings (1791-1859), an African-American tailor and abolitionist, patented a dry-cleaning process, but it was not until the mid-1800s that entrepreneurs instituted formal dry cleaning. Various legends describe how chemical solvents came to light. Some credit a maid who spilled turpentine on a soiled dress; another version describes a French sailor who fell into a barrel of turpentine and came out with a spotless uniform. In 1845 Parisian dyer Jean-Baptiste Jolly spilled kerosene on a soiled tablecloth and discovered that the substance cleaned the spot. He coined the term "dry cleaning" to differentiate it from regular soap and water wash; his firm, Jolly-Belin, became Europe's first professional dry cleaner. By 1897, Ludwig Anthelin of Leipzig, Germany, discovered that application of carbon tetrachloride gave acceptable results without creating a fire hazard. Because the solution was an irritant, fans to ventilate solvent storage chambers were necessary to protect workers from severe respiratory distress. Around 1910, American dry cleaners were capitalizing on European successes. Valet shops and pressing clubs expanded into adjuncts for laundries, where a variety of services, including alterations, reweaving, and repairs led to full-time clothing care.
By 1919, dry cleaning had grown into a$55 million industry and cleaners were searching for improved, nonflammable solvents. Around 1930, dry cleaners introduced a less harmful chemical named Stoddard solvent to honor W.J. Stoddard, president of the National Institute of Dry Cleaning. Other nonflammable synthetic solvents, such as trichloroethylene and perchloroethylene, were developed for use in both professional cleaning plants and coin-operated machines. The usual procedure for dry cleaning required that clothing be inspected, tagged, then sorted as to color, fiber, and weave. Delicate fabrics--such as cashmere, angora, ornate lace, leather, suede, fur, and other fragile materials--and seriously stained garments were spot-cleaned by hand. Ornamentation, belts, lace collars and cuffs, fur pieces, and shoulder pads were removed for individualized care. The soiled items were churned in a large drum similar to a washing machine through mists of solvent and detergent, which loosened and suspended stains and grime. Then the bundle underwent a second cycle to agitate and remove the chemical cleaning agents. Used solvent was filtered or distilled to remove soil and to allow the reuse of the chemicals. To complete the job, a spotter brushed and steam-gunned stubborn spots. Finally, the clothing was dried. To remove wrinkles and restore shape and texture to the fabric at the conclusion of the cleaning process, pressers shaped and steamed garments with a professional-sized iron or over a basket-shaped hoop.
A half century later the industry still uses the same basic methods and has grown to be a $2.8 billion enterprise. However, the industry has not been without its difficulties. In 1960, the advent of permanent-press materials introduced the public to the ease and low cost of wash-and-wear clothing, thereby lessening dependence on professional cleaning. A second blow to the industry was the environmental movement, which urged city councils to regulate or ban the release of noxious solvents into the atmosphere.
In the last few decades several advances have been made in dry cleaning technology. One advance involves the creation of a sensor which helps optimize the amount of moisture used in the dry cleaning process. Despite the name, dry cleaning does involve some small amounts of water. Too much water causes fabrics to wrinkle and shrink and too little leads to residual spotting. A relative humidity transmitter developed in the mid 1990's has been used to help control the exact amount of moisture.
In 1997, Micell Technologies, Inc. developed technology which uses liquid carbon dioxide, instead of harmful chlorinated compounds, to remove dirt and grease from fabric. Due to the cost of the high pressure equipment used in this process, it may take a while for this technology to replace existing equipment. Micell's key to this technology was the discovery of a surfactant, or detergent, which was soluble in liquid carbon dioxide.
The latest development in dry cleaning is not really a dry cleaning process at all. In 1998 both Procter & Gamble's and Creative Products Resources introduced home dry cleaning kits which are designed to allow consumers to treat dry cleanable garments at home. Both systems consist of a non-woven fabric pad which is saturated with a cleaning solution. This pad is used to pre- treat the stained area of the garment and is placed in a large resealable plastic bag along with the garment. This bag is tightly sealed, placed in a dryer, and tumbled with mimimal heat. This heat helps loosen the pre-treated stain while the fragrance and other chemicals in the pad penetrate throughout the fabric leaving it refreshed. While this technology is not anticipated to completely replace existing dry cleaning operations it may have a serious impact on the industry.
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