Professional garment care dates back to the days of Pompeii when early cleaners were called "fullers". They used lye and ammonia in early laundering and a type of clay called "fuller's earth" to absorb soils and greases from clothing too delicate for laundering.
While 1690 is the first published reference to the use of spirits of turpentine for removing tar and varnish from fabrics, it wasn't until 1716 that turpentine began to be used regularly as a "dry cleaner" for grease and oil stains to supplement wet-cleaning processes. Down through the ages, turpentine, a distillation of pine pitch, has had several names: oil of turpentine, spirits of turpentine, camphene, and "turps".
Even before organic solvent was used to clean garments by immersion methods, the cleaner of clothes was known as a "degrasseur", a degreaser of textiles able to remove grease and fat stains from cloth. The French name for cleaner was teinturier-degraisseur (a dyer-degreaser). "Degraisseur" was the common term applied to a master dyer who specialized in both dyeing and cleaning garments.
In the early 1900s, dry cleaners began using spirits of turpentine, called "camphene", as a dry cleaning solvent. This discovery quickly spread to other countries on the continent and later to the British Isles, led by John Pullar and Sons in Perth, Scotland. The new process became known as "French Cleaning", named for the earlier reputation and fame gained in France. This term continues to be used today signifying a special process requiring highly skilled handwork.
The first use of dry cleaning soap was in Germany. In 1928, Stoddard solvent, which had a higher flash point than other solvents currently being used, was introduced. In 1932, chlorinated hydrocarbons-non-flammable synthetic solvents-were introduced in the United States.
Two types of solvents are currently used for dry cleaning; perchlorethylene (PREC) and petroleum. While both perform essentially the same function, their structures and properties are different.
A solvent must meet certain criteria in order to be used for dry cleaning. For example, an acceptable dry cleaning solvent must be free of objectionable odours, and certainly must not leave residual odour in garments after drying. In additional, the solvent should be able to be safely heated to its boiling point for distillation purposes so that it may be continually cleaned and recycled.
In order to be used for safe and effective dry cleaning; a solvent must have the capability to dissolve solvent-soluble substances. This "solvent power" must fall in a range that will effectively remove solvent-soluble soils (fats, oils and greases) without risking any damage to common textile fibers and dyes.
Solvents that are appropriate for use in dry cleaning perform a number of functions. Dry cleaning solvents dissolve solvent-soluble soils, such as oils, waxes, and greases. They also act as a carrier for insoluble soils. Solvents carry detergent, which in turn carries water to remove water-soluble soils. Lastly, in combination with mechanical action, solvents produce a flushing action on fabrics to aid in cleaning.
The actual cleaning process for dry cleaning is similar to the washing process. Clothes are separated by weight, finish, and colour. Heavyweight clothes are separated from lightweight clothes. Delicate clothes are further separated and cleaned separately. Finally, light colours and dark colours are cleaned separately. Clothes with spots are also separated for spot cleaning.
The clothes are cleaned in machines that look like large, over-sized front load washing machines. However, this machine requires cleaning solvent, which is used over and over and continually cleaned during the cleaning process by recycling the solvent through filters and distillation.
With each load of clothes cleaned, some distillation takes place. As the clothes are dried, the solvent vapours are passed over condensation coils where the solvent is again returned to its clear liquid form and reused. Additionally, a portion of solvent from each load is pumped into a still where it is heated and turned into vapour, which are condensed and returned to a clear liquid form.
Finally, after the clothes are removed from the machine, they are checked for spots and additional cleaning if necessary. The clothes are steam finished and are ready to be assembled for order completion.
