Dry cleaning refers to the use of chemical solvents to wash clothes to remove stains a dry in dry out washing method. Because the water does not directly contact the clothes during the washing process, it is called dry cleaning. Usually, organic solvents are used, such as tetrachloroethylene, petroleum solvents, etc. At the same time, the auxiliary filler (such as soap oil) will rub, roll and rinse the water solvent dirt by mechanical force. The main feature of dry cleaning is to avoid damage to clothing fabrics caused by water washing, no shrinkage, no deformation, good color protection, not easy to cause clothing fading, soft feel, easy to iron and thoroughly clean oil or stains on clothing.
Dry cleaning originated in Paris, France, in the early 19th century, there are two legends, one is a chance to touch the lamp oil spilled on a dirty tablecloth, found that it removed the stain on the dirty tablecloth; The second is that the oil stains on a garment soaked in benzene are removed. Thus, the role of hydrocarbons in removing oily stains was discovered, and its cleaning ability was recognized. Joly, Paris, 1984. Berin’s plant avoids the shrinkage and decoloration problems of traditional washing by using dry cleaning, which starts with petroleum-based solvents.
Petroleum solvents, such as benzene, kerosene and gasoline, are flammable solvents, and the dry cleaning industry has become a dangerous industry. The most original dry cleaning method is to soak, scrub, wring out, air dry, and naturally volatilize the clothes with gasoline solvent by hand, which is both a waste of solvent and unsafe. In 1926, the trial production of a petroleum solvent for dry cleaning “Stoddard” (Stoddard), and began to use dry cleaning machine, cleaning in the machine, deliquid, waste is less, but flammable, explosive insecurity is still serious.
In the 1930s, developed countries began to use trichloroethylene chemical solvents as dry cleaning solvents, to solve the flammable and explosive problem, it is said that in the 1960s, China also introduced this solvent dry cleaning machine. But trichloroethylene degreatability is strong, the physical and chemical properties of the fiber has a certain damage to the equipment has a strong corrosion, its toxicity is strong, the operator also has a certain harm, during this period, dry cleaning has also used carbon tetroxide, trichlorotrifluoroethane, etc., due to the toxicity of these solvents have been banned, some dye fading and other reasons have not been continued to use.
In the 1940s, foreign developed countries began to use tetrachloroethylene, it overcame the shortcomings of trichloroethylene, the performance is relatively stable, the KB value is relatively high cleaning degree, the toxicity is relatively low trichloroethylene, and it is recognized by the laundry industry as a better dry cleaning solvent, which has been used so far. Tetrachloroethylene (also known as perchloroethylene) is a colorless transparent liquid that does not burn easily, has a smell similar to ether, is insoluble in water, soluble in ethanol, ether and benzene, and actually has a relationship with hydrocarbons, namely hydrocarbons. One of the preparation methods of tetrachloroethylene is the high temperature chlorination method of hydrocarbons, which is prepared by the oxidation pyrolysis of methane, ethane, propane, propylene and other hydrocarbons at 50-500℃. Mainly used as solvent, dry cleaning agent, fire extinguishing agent, smoke agent, animal and plant oil extraction agent, etc. It was even used as a human dewormer. When tetrachloroethylene is used as a dry cleaning agent to clean the fabric, the fiber does not expand or shrink, does not affect the fiber structure, and will not fade the colored fabric, so it is suitable for the dry cleaning of natural and synthetic fibers, the impregnation of fur, and the cleaning of raw wool. It is especially suitable for high and middle grade fur and its products, which can make the fur loose, bright and soft.
Since the advent of tetrachloroethylene, it has been used for more than 70 years as a major grease removal cleaning agent in the machinery manufacturing industry, and it has also been used safely in the laundry industry for more than 60 years. As a chemical solvent has its advantages and disadvantages, its strong oil removal, both in the machinery manufacturing industry and laundry industry, have played an extremely important role, especially its distillable recycling and safety and reliability in the laundry industry. By the early 1960s, the laundry industry as a flammable oil solvent substitute and rapid growth, has also been widely used in our country.
