HK1036641B - Dry cleaning method - Google Patents

Description

Dry cleaning method

Technical Field

The present invention is in the general field of dry cleaning of garments, fabrics, textiles and the like. The present invention relates to a more unique method and apparatus for dry cleaning fabrics using a solvent that has not previously been used in dry cleaning machines. The invention is particularly useful in dry cleaning equipment using silicone-based solvents which have desirable flash point values (in excess of 140 degrees f, i.e., in excess of 60 degrees c), are safe and reliable (do not discolor, do not wrinkle) to fabrics during specially designed dry cleaning processes, and have superior fatty acid, grease, and grease dissolution characteristics.

Background

Dry cleaning is an important industry throughout the world. There are 4 thousands of dry cleaners in the united states alone (many of which have chains).

Dry cleaning is an indispensable industry in today's economy. Many garments (and other articles) must be dry cleaned to remove body oils and keep clean while preventing shrinkage and discoloration.

The dry cleaning agent generally used so far is Perchloroethylene (PERC). Its use presents a number of disadvantages including its own toxicity and odor. The machines and apparatuses widely used so far have been designed exclusively for the use of perchloroethylene. This is also another limiting factor in the industry.

Another problem in this field is that different fabrics require different systems to prevent the fabrics from being damaged during dry cleaning.

Previous dry cleaning processes have involved the use of various solvents and suitable machinery to accomplish the washing. The most commonly used solvent in the past was perchloroethylene (commonly known as PERC). Perchloroethylene has a very good cleaning effect, but its major drawbacks are health hazards and environmental pollution (i.e., its use can cause many types of cancer, contamination of groundwater, damage to aquatic life). In some areas, perchloroethylene has been banned. In addition, other solvents such as petroleum-based solvents, glycol esters, ethers have also been tried in the past. The cleaning effect of the various solvents and the suitability for use with fabrics can be analogized to perchloroethylene.

The present invention differs significantly from the conventional art in that it uses a non-perchloroethylene solvent, as described below, which has good characteristics, and in that the method used comprises a dry cleaning machine apparatus specifically designed for said solvent.

The only cyclic siloxane component described for washing purposes is disclosed by Kasprzak in U.S. patent No. 4,685,930. However, the disclosure is filed only for spot cleaning. There is neither disclosure of soaking laundry in cyclic siloxanes nor any suggestion of using cyclic siloxanes in dry cleaning machines. Furthermore, there is no suggestion of a continuous process such as soaking the textile in cyclic siloxane, agitating, spinning, partially vacuuming and heating to dry, clean the laundry in a batch manner, and remove fats, grease and other soils from a large volume of laundry.

Disclosure of Invention

The present invention comprises a new dry cleaning system and method in which the improved dry cleaning machine is used in combination with a specialized solvent derived from an organic/inorganic hybrid (organosiloxane). Among such organosiloxanes, one group is known as cyclic siloxanes. Such cyclic siloxanes act as the basic chemical component of the solvent material, making dry cleaning systems more effective. The cyclic siloxane-based solvent makes the system more beneficial to environmental protection and more effective in washing fabrics and the like than the prior system. The silicone component is used in a dry cleaning machine to carry out the method of the present invention. In a preferred embodiment, the process comprises the steps of: placing clothes in a washing basket; soaking the washings in the siloxane component and stirring the washings; removing a substantial portion of the siloxane component; centrifugally drying the washed objects; applying negative pressure to the washed object and raising the temperature; after cooling and returning to atmospheric pressure, the laundry was removed from the washing basket.

The dry cleaning solvent of the present invention further contains a detergent, a disinfectant, a suspending agent and a brightener.

The main object of the present invention is to provide a dry cleaning solvent and technique which are environmentally friendly.

A second object of the present invention is to provide a dry cleaning method using a solvent which does not damage the laundry.

A third object of the present invention is to provide a dry cleaning solvent which does not precipitate or accumulate on the laundry, and is a low strain source.

A fourth object of the present invention is to provide a dry cleaning solvent having unique flammability characteristics that provides a flash point and a fire point that are separated by at least 10 degrees fahrenheit (-12.22 degrees celsius) and thus self-extinguishes between the flash point and the fire point.

A fifth object of the present invention is to provide a dry cleaning solvent that can be heated to room temperature, (above 70 degrees fahrenheit, i.e., above 22.1 degrees celsius) to further improve and speed the washing process without damaging the fabric.

It is a sixth object of the present invention to provide a dry cleaning solvent having a low surface tension of less than 18 dynes/cm, which better penetrates the fabric fibers, removes stains, and more easily removes the solvent from the garments.

The foregoing objects, and other objects and advantages of the present invention, will become apparent to those skilled in the art from the following description of the preferred embodiments.

Drawings

The foregoing objects and advantages of the invention, as well as additional objects and advantages thereof, will be better understood from the following detailed description of the invention, the preferred embodiments, and the accompanying drawings.

FIG. 1 is a block flow diagram of one embodiment of the present invention.

Detailed Description

The dry cleaning process is unique and employs common liquid, cyclic siloxane solvents that are commonly used in the cosmetic and pharmaceutical industries. The following cyclic siloxanes are more unique: octamethylcyclotetrasiloxane (tetramer), decamethylcyclopentasiloxane (pentamer), dodecamethylcyclohexasiloxane (hexamer). Such liquids have never been disclosed as being useful in dry cleaning machines or as dry cleaning solvents. The above tetramer and pentamer compositions, in their pure form, are not fully adaptable to dry cleaning processes. It is improved in the dry cleaning method of the preferred embodiment. The improved form is as follows: adding sand suspension additive to prevent dirt such as dust from re-precipitating in the washing and rinsing processes; adding a water-soluble stain cleaning agent; and a sterilizing and disinfecting agent to eliminate all microorganisms and bacteria present in the laundry.

The following steps more specifically describe the dry cleaning process of the preferred embodiment:

in step 1, garments, or other articles to be dry cleaned, are placed in a vertical washing and drying machine having a horizontal agitated wash basket (also known to those skilled in the art as a wash basket). The basket has a plurality of apertures, preferably 1/8-3/8 inches (0.3175-0.9525 cm) in diameter per aperture.

In step 2, a wash cycle is introduced into the solvent consisting of the cyclic siloxane tetramer and pentamer. The preferred combination is 80% tetramer and 20% pentamer by weight. The additives used to condition the mixture may be added prior to the wash cycle and need not be part of the solvent. The additives, i.e., the detergent and suspending agent, allow the solvent to complete the entire washing process of the garment. Solvent is pumped from the storage tank into the wash basket. The washings are agitated, the clothes are mechanically rubbed, the penetrating solvent removes dirt and body fat from the fabric fibres, said agitation being continued for 3-10 minutes. The solvent is then pumped out of the wash basket through a valve, through an activated carbon or clay filter system, to remove contaminants entrained during the wash, and into a holding tank.

In step 3, spin-drying the cleaned clothes, preferably for 3-5 minutes, at a rotation speed of about 350 and 1000RPM (revolutions per minute); preferably 450 rpm to 750 rpm. The process can make the residual solvent in the washings not more than 3%. The higher the speed of rotation, the more centrifugal force is applied to the rotating wash basket and the faster the solvent is removed. The low surface tension of the solvent maximizes the effectiveness of the solvent removal during centrifugation.

In step 4, the garments are tumbled in a laundry basket and heated to 120-. Pressurized steam is injected through the coiled pipe, and a circulating ventilator is used for heating air in the washing basket to complete the heating process. At the same time, a partial vacuum may be created within the machine, providing a negative pressure of 500-600 mmHg (66.67Kpa to 80Kpa) (760 mmHg atmospheric pressure, i.e., 101.325 kPa). In this heating cycle, the solvent mixture is vaporized and carried by the circulating air into the condensing coil, and the vapor in the main gas stream is condensed into a liquid state for collection. The gas stream may be reheated in a closed loop system. Typically, the solvent mixture is removed from the wash over 15-20 minutes.

In step 5, the heating cycle is stopped and the cooling cycle is started. The temperature may drop from 140 degrees fahrenheit (60 degrees celsius) to 100 degrees fahrenheit (38 degrees celsius). This process is accomplished by removing the vacuum and circulating air through the cooling tubes until the cooling process is complete.

Under the condition of approaching or being lower than the body temperature, the clothes are taken out from the machine, the washing process is finished, and the secondary wrinkling can be reduced. When the temperature is high, the film is taken out, and wrinkles are caused.

The preferred embodiments of the method and apparatus of the present invention disclosed herein are to be considered in all respects as illustrative and not restrictive.

Claims (18)

1. A method of dry cleaning articles comprising the steps of:

-placing the laundry to be dry-cleaned in the machine;

immersing said laundry to be dry-cleaned in a dry-cleaning solvent comprising a cyclic siloxane composition;

agitating the wash in the cyclic siloxane composition;

placing the washings under vacuum to control the flash point of the cyclic siloxane;

removing the silicone composition from the wash by centrifugation after subjecting the wash to vacuum conditions;

the silicone composition is removed from the laundry by exposing the laundry to circulating air.

2. The method of claim 1, wherein the temperature of the circulating air is maintained at 49-60 degrees celsius during the removing of the silicone composition from the laundry.

3. The method of claim 2, wherein said laundry is subjected to said vacuum while maintaining said temperature.

4. The method of claim 3, wherein the vacuum is maintained between 66.67Kpa and 80 Kpa.

5. The method of claim 2, wherein maintaining the temperature comprises injecting pressurized steam through the coil to heat the air.

6. The method of claim 2, further comprising the step of cooling the laundry to a temperature below 38 degrees celsius to prevent wrinkling of the laundry prior to removing the laundry from the machine.

7. The method of claim 1, further comprising the step of cooling the laundry to a temperature below 38 degrees celsius to prevent wrinkling of the laundry prior to removing the laundry from the machine.

8. The method as set forth in claim 7, further comprising the step of reducing the vacuum pressure during cooling of the laundry.

9. The method of claim 1, wherein the cyclic siloxane composition comprises a pentamer, tetramer cyclic siloxane as a solvent.

10. The method of claim 9 wherein the tetramer is 80% by weight and the pentamer is 20% by weight.

11. The method as set forth in claim 1 wherein the cyclic siloxane composition consists of a mixture of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane.

12. The method as set forth in claim 1, wherein the cyclic siloxane composition consists of a mixture of at least two cyclic siloxanes.

13. The method of claim 1, further comprising the step of placing the wash load in a wash basket.

14. The method of claim 1, wherein the centrifuging results in no more than 3% cyclic siloxane remaining in the wash.

15. The method of claim 1, wherein the laundry is agitated in the cyclic siloxane composition for a period of time ranging from 3 to 10 minutes.

16. The method as set forth in claim 1, further comprising the step of filtering the cyclic siloxane composition to remove soil that enters the cyclic siloxane composition when the wash is agitated.

17. The method of claim 1, wherein the dry cleaning solvent further comprises a cleaning agent, a disinfectant, a suspending agent, and a gloss enhancer.

18. The method as set forth in claim 1, further comprising the step of cooling the laundry by circulating air through the cooling duct.