Dry cleaning method and solvent

Description

The invention relates to the general field of dry cleaning (dry cleaning) of garments, textiles, fabrics and the like. More particularly, the invention relates to a method and apparatus for dry cleaning fabrics using a solvent not previously used in dry cleaning machines. The invention also relates to a dry cleaning apparatus in which a silicone-based solvent is used in a specially designed dry cleaning process, which has a desired flash point (above 60 °C), fabric-friendly properties (does not remove paint or shrink the fabric) and a higher solubility against fatty acids, grease and oils, Dry cleaning is a major industry worldwide. In the United States alone, there are over forty thousand dry cleaners (many in multiple locations). The dry cleaning industry is a vital industry in today's economy. Many items of clothing (and other items) need to be dry cleaned to keep them clean (by removing body fats and oils) and presentable (to prevent the clothes from shrinking and fading). The most widely used dry cleaning solvent to date is Perc. Perc has several disadvantages, including its inherent toxicity and odor. ~2~ Although widely used, machines are still manufactured specifically for use with Perc. This is another limiting factor in the industry. A further problem in this area is that in the systems currently used, different fabrics require different treatments to prevent damage to the fabrics during the dry cleaning process. Prior art dry cleaning processes involve the use of various solvents in conjunction with appropriate machinery to perform the cleaning. The most widely used solvent in recent times is perchloroethylene (referred to as Perce). Perce has the advantage of being an excellent cleaning solvent, but the disadvantage is that it poses significant health and environmental risks (i.e., it has been linked to several forms of cancer and is very destructive to groundwater and aquatic life). In some areas, the use of Perce is no longer permitted. In addition, other solvents, such as mineral oil-based solvents and glycol ethers and esters, have been tried and used in the past. These various solvents have been used with mixed cleaning results and uncertain fabric / textile compatibility compared to the results obtained with Perce. The present invention differs from the prior art in that it is based on the use of a non-Perc solvent with excellent properties, as described below, and is used in a process involving a chemical purification machine specifically designed for this solvent. The only use of a cyclic siloxane composition for cleaning purposes is disclosed in U.S. Patent No. 4,685,930 (Kasprzak). However, the disclosure therein is limited to stain removal applications. Neither is there any mention of dipping articles in cyclic siloxane, nor is there any reference to the use of cyclic siloxane in a dry cleaning machine. Furthermore, there is no reference to the articles being dipped in such cyclic siloxane being subjected to continuous agitation, centrifugation, partial vacuum, and heating in the bulk processing of dry cleaning articles for the removal of fats, oils, greases, and other contaminants from a large number of diverse articles of clothing. The invention includes a novel dry cleaning system and method in which specially designed or modified equipment is used in a with a specific solvent derived from an organic / inorganic hybrid (organic silicone). Within the class of organic silicones is a group known as cyclic siloxanes. The cyclic siloxanes are the basis of the solvent chemistry that allows this dry cleaning system to be very effective. The cyclic siloxane-based solvent allows the system to provide an environmentally friendly process that is more effective in cleaning fabrics and the like than any system known to date. A. The siloxane composition is used in a dry cleaning machine to carry out the process of the invention, The fundamental objective of the invention is to provide a dry cleaning process using environmentally friendly solvents and techniques. Another object of the invention is to provide a method where the articles to be cleaned are not damaged by the solvent. It is a further object of the invention to provide a dry cleaning solvent that does not deposit and / or accumulate in clothing and does not cause allergies. It is also an object of the invention to provide a dry cleaning solvent that has unique flammability properties, where there is at least a 10°C difference between the flash point and the burn point, whereby the solvent self-suffocates between the flash point and the burn point. It is a further object of the invention to provide a dry cleaning solvent which can be heated above room temperature (above 20°C) without damaging the fabric, thus further improving and accelerating the cleaning process. It is a further object of the invention to provide a dry cleaning solvent having a surface tension of less than 1.8 N / nh to better penetrate the fabric fibers for soil removal and easier removal of the solvent from the fabric, The invention is a method for dry cleaning articles, during which the articles to be dry cleaned are placed in an apparatus, the articles to be dry cleaned are immersed in a dry cleaning liquid, the articles are mixed in the dry cleaning liquid, the method is characterized in that the dry cleaning liquid contains a cyclic siloxane composition, and during the method the cyclic siloxane composition is removed from the articles by centrifugation; the cyclic siloxane composition is removed by heated air circulated around the articles; the temperature of the circulated air is 49 - 60 °C X» * is maintained at a temperature during removal of the cyclic siloxane composition from the articles; and by cooling the articles to below 38 °C prior to removal from the apparatus to prevent wrinkling of the articles, and articles subjected to chemical cleaning are placed under vacuum after mixing but before centrifugation and before exposure to heated air. The invention includes a method for dry cleaning articles, comprising: placing the articles to be cleaned in an apparatus; immersing the articles to be dry cleaned in a dry cleaning liquid; mixing the articles in the dry cleaning liquid, the method being characterized in that the dry cleaning liquid contains a cyclic siloxane solvent and placing the articles under vacuum during the method; removing the cyclic siloxane composition from the articles by centrifugation after placing the articles under vacuum; removing the cyclic siloxane composition from the articles by circulating air around them; maintaining the temperature of the circulated air at 49 ~ 80:oC after placing the articles under vacuum during the removal of the cyclic siloxane composition from the articles; and preventing the articles from wrinkling by cooling them below 38 X before removing them from the apparatus. It is preferred that the cyclic siloxane composition comprises pentameric and tetrameric cyclic siloxanes as solvents, preferably the tetrameric cyclic siloxane is present in an amount of 80% by weight and the pentameric cyclic siloxane is present in an amount of 20% by weight. Preferably, the cyclic siloxane composition comprises a mixture of octamethyldicyclotetrasiloxane and decamethylcyclopentasiloxane. It is also advantageous if the dry cleaning fluid also contains detergent, disinfectant, suspending agents and / or fresh ingredients (invigorators). The vacuum is preferably maintained at a value between 66.87 kPa and 80 kPa. Optionally, the method further includes a step of filtering the cyclic siloxane composition to remove impurities introduced into the cyclic siloxane composition during mixing of the articles. In a preferred embodiment, the method comprises the following steps: placing the articles in a washing drum; mixing the articles and the siloxane composition in which the articles have been soaked; removing the majority of the siloxane composition; centrifuging the articles; subjecting the articles to a partial vacuum and « * « 4 4. 4.Χ * ♦ « »· * » Μ * *· subjected to elevated temperature; then after cooling the articles, remove the articles from the drum and restore the pressure to the ambient value, The aforementioned objects and advantages of the invention will become apparent to those skilled in the art from the detailed description of the preferred embodiments and the accompanying drawings. Figure 1 is a block diagram of the steps of a method illustrating one embodiment of the invention. The present dry cleaning process is a unique process, especially due to the use of a generally known liquid group of cyclic siloxanes used in cosmetics and topical medications. These cyclic siloxanes are more specifically known as octamethylcyclotetrasiloxane (tatramer) and decamethylcyclopentasiloxane (pentamer). These liquids have never been disclosed as an alternative dry cleaning solvent for use in dry cleaning machines. The above combinations of teframer and pentamer alone are not entirely suitable for dry cleaning in their pure form. Therefore, they have been modified in the dry cleaning process according to the preferred embodiment of the process.The modification was made by adding the following substances: soil suspending additives to prevent dirt from being redeposited during the wash and rinse cycles; detergents for water-based stains and disinfectants to kill bacteria and other microorganisms present on all clothes. The following steps describe in more detail the dry cleaning process according to the preferred embodiment, In step 1, the garments or other items to be dry cleaned are placed in a vertically combined washer-dryer with a horizontally rotating, agitating cleaning drum (cleaning basket). The drum has a number of holes or perforations, preferably each hole is 0.32-0.95 cm in diameter, In step 2, the wash cycle is started with a solvent consisting of a combination of tetramer and pentamer cyclic siloxane. 80 wt% tetramer and 20 wt% pentamer is the preferred combination. The additives modifying the above mixture can be added separately, just before the wash cycle, and do not need to be part of the solvent composition. The use of such additives, i.e. detergents and suspending agents, allows the solvent, ♦*»* * « -8to provide a thorough cleaning of clothes. The solvent is pumped from a storage tank into the cleaning drum. The items to be cleaned are mixed in such a way that the mechanical abrading of the clothes and the penetration of the solvent dissolve and release dirt, debris and body oils from the fabric fibers, the mixing lasting 3-15 minutes or longer. The solvent is then pumped back from the drum into the storage tank through an activated carbon and / or clay filter system to remove any contaminants that may have entered the solvent during the wash cycle. In step 3, the cleaned batches are centrifuged, preferably for 3-5 minutes, at a speed of about 350-1000 rpm (revolutions per minute); preferably at a speed of 450-750 rpm. This operation leaves a maximum of 3% solvent residue in the cleaned batches. The higher the speed, the faster the solvent is removed due to the centrifugal force of the rotating drum. The very low surface tension of the solvent maximizes the efficiency of solvent removal by centrifugation. In step 4, the garments are spun in the drum and heated to a temperature of 48-80°C. This is done by passing pressurized steam through a tube bundle, which heats the air inside the drum using a circulating nozzle. While this is happening, a partial vacuum is created inside the machine with a vacuum pressure of 86-79 kPa (where atmospheric pressure is 9.88 kPa). During the heating cycle, the solvent is evaporated and is conveyed by circulating air to a cooled condensing tube bundle, which condenses the solvent collected with the main air stream from vapor to liquid. Over time, usually within 15-20 minutes, all the solvent is removed from the garments. In step 5, the heating cycle is stopped and the cooling cycle is started. The temperature is reduced from 60°C to below 38°C. This is done by breaking the vacuum and circulating air through the cooled tube bundle until the process is complete. The cleaning process is complete when the garments are removed from the machine at a temperature close to or below body temperature to reduce secondary wrinkling. Removing garments at high temperatures will cause wrinkles.

Claims

Patent claims 1. A method for dry cleaning articles, comprising placing the articles to be dry cleaned in an apparatus, immersing the articles to be dry cleaned in a dry cleaning liquid, mixing the articles in the dry cleaning liquid, characterized in that the dry cleaning liquid contains a cyclic siloxane composition and during the method the cyclic siloxane composition is removed from the articles by centrifugation: the cyclic siloxane composition is removed by circulating heated air around the articles; the temperature of the circulated air is maintained at a temperature of 49-60°C during the removal of the cyclic siloxane composition from the articles; and by cooling the articles below 38°C prior to removal from the apparatus to prevent shrinkage of the articles, and by placing the articles subjected to chemical separation under vacuum after mixing but before centrifugation and before exposure to heated air.

2. The method according to claim 1, characterized in that the cyclic siloxane composition contains pentameric and tetrameric cyclic siloxane as solvent.

3. The process according to Claim 2, characterized in that the tetrameric cyclic siloxane is present in an amount of 80% by weight and the pentameric cyclic siloxane is present in an amount of 20% by weight.

4. The method according to Claim 1, characterized in that the cyclic siloxane composition comprises a mixture of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, 5. The method of claim 1, wherein the cyclic siloxane composition comprises a mixture of at least two forms of cyclic siloxanes. * ·« δ. The method of claim 1, further comprising the step of placing the articles in a cleaning drum.

7. The method of claim 7, wherein the cleaning drum comprises a plurality of holes having a diameter of 0.3175 to 8.9525 cm.

8. The method of claim 1, further comprising the step of subjecting said articles to a partial vacuum during drying.

9. The method of claim 1, wherein the centrifuging comprises spinning the articles at a speed of 350 to 1000 rpm.

10. The method of claim 1, wherein the centrifuging comprises rotating the articles at a speed of 450 to 758 revolutions per minute.

11. The method of claim 1, wherein the centrifugation leaves no more than 3% of the cyclic siloxane composition in the articles.

12. The method of claim 1, wherein the articles in the cyclic siloxane composition are mixed for 3 to 10 minutes.

13. The method of claim 1, further comprising the step of: filtering the cyclic siloxane composition to remove impurities introduced into the cyclic siloxane composition during mixing of the articles.

14. The method of claim 1, wherein the dry cleaning liquid comprises detergent, disinfectant, suspending agent(s) and colorant(s). X * 15. The method of claim 1, wherein the articles are cooled by circulating air through a cooled tube bundle. 18.A method for dry cleaning articles, comprising: placing the articles to be cleaned in an apparatus; immersing the articles to be dry cleaned in a dry cleaning liquid; mixing the articles in the dry cleaning liquid, characterized in that the dry cleaning liquid contains a cyclic siloxane composition; and placing the articles under vacuum during the method; removing the cyclic siloxane composition from the articles by centrifugation after placing the articles under vacuum; removing the cyclic siloxane composition from the articles by circulating air around them; maintaining the temperature of the circulated air at 49-60°C during the removal of the cyclic siloxane composition from the articles after placing the articles under vacuum; and preventing shrinkage of the articles by cooling them below 38°C prior to removal from the apparatus.

17. The method of claim 16, wherein the cyclic siloxane composition comprises pentameric and tetrameric cyclic siloxanes as solvents.

18. The method of claim 17, wherein the tetrameric cyclic siloxane is present in an amount of 5 wt% and the pentameric cyclic siloxane is present in an amount of 20 wt%.

19. The method of claim 16, wherein the cyclic siloxane composition comprises a mixture of octamethyldichlorotetrasiloxane and decamethylcyclopentasiloxane. χ* -to- 'ü:

20. The method of claim 16, wherein the cyclic siloxane composition comprises a mixture of at least two forms of cyclic siloxanes.

21. The method of claim 18, wherein the centrifuging comprises rotating the articles at a speed of 350 to 1000 revolutions per minute.

22. The method of claim 18, wherein the centrifuging comprises rotating the articles at a speed of 460 to 750 revolutions per minute.

23. The method of claim 18, wherein the centrifugation leaves no more than 3% of the cyclic siloxane composition in the articles.

24. The method of claim 18, wherein the articles in the cyclic siloxane composition are mixed for 3 to 10 minutes.

25. The method of claim 16, further comprising the step of filtering the cyclic siloxane composition to remove impurities introduced into the cyclic siloxane composition during the mixing of the articles.

28. The method of claim 18, further comprising a detergent, a disinfectant, a suspending agent(s) and a colorant(s).

27. The method of claim 16, wherein the articles are cooled by circulating air through cooled tube bundles, 28. The method of Claim 18, wherein the vacuum is maintained at 68.87 kPa - 80 kPa.

29. The method of claim 18, wherein the vacuum is reduced during cooling of the articles. t ; :

4. ϊ. 11 30. The method of claim 18, wherein pressurized steam is passed through a tube bundle to heat the air while maintaining the temperature.