DE60222808T2 - METHOD OF DRY CLEANING USING COMPRESSED CARBON DIOXIDE - Google Patents

Abstract

Disclosed is a method for the removal of stains from articles, especially fabric, using densified carbon dioxide. The invention is concerned with a method of dry cleaning an article comprising the successive steps of (a) contacting the article with a fluid dry cleaning composition containing densified carbon dioxide at a temperature between -20 and 60° C. and a pressure between 1 and 100 MPa, so as to allow stains to dissolve and/or to disperse into the fluid dry cleaning composition and (b) separating the article and the fluid dry cleaning composition; wherein the fluid dry cleaning composition comprises an ionic surfactant in a concentration between 0.01 and 15% by weight of the carbon dioxide and wherein during step a) at least 10%, preferably at least 30%, of said ionic surfactant is present in an undissolved solid form.

Description

TECHNICAL AREA

The The present invention provides a method for removing stains from articles, mainly Tissue, using compressed carbon dioxide. Insbesondre The invention is concerned with a method for dry cleaning an article comprising the successive steps of the article Contacting the article with a fluid dry cleaning composition, the compressed carbon dioxide at a temperature between -20 and 60 ° C and contains a pressure between 1 and 100 MPa in order to allow that stains dissolve and / or disperse in the fluid dry cleaning composition, and the separation of the article and the fluid dry cleaning composition, wherein the fluid dry cleaning composition contains a surfactant.

BACKGROUND OF THE INVENTION

densified especially supercritical fluid carbon dioxide has been used as an alternative to halohydrocarbon solvents, which are used in the conventional dry cleaning proposed.

Compressed carbon dioxide is a non-toxic, inexpensive, reusable and environmentally friendly solvent to remove debris in the dry cleaning process. It is known that supercritical carbon dioxide is effective in removing nonpolar stains such as motor oil when combined with a viscous cleaning solvent, particularly mineral oil or petroleum jelly, as disclosed in U.S. Pat US 5,279,615 is described.

The solvency of compressed carbon dioxide is relative to ordinary liquid Solvent low, and the carbon dioxide solvent alone is with hydrophilic stains such as grape juice, Coffee and tea and hydrophobic stains that consist of several ingredients exist, such as lipstick and candle wax, less effective unless surfactants and solvent modifiers are added.

A cleaning system that combines certain anionic or nonionic surfactants with supercritical fluid carbon dioxide is known in the art DE-A 39 04 514 described. These anionic and nonionic substances, such as alkylene benzene sulfates and sulfonates, ethoxylated alkylene phenols, and ethoxylated fatty alcohols, were particularly effective when combined with a relatively large amount of water (greater than or equal to 4%).

The US 5,676,705 describes a method of dry cleaning fabrics comprising contacting the soiled fabric with a dry cleaning system comprising densified carbon dioxide and from 0.001% to 10% by weight of a surfactant compound that is soluble in the compressed carbon dioxide. The examples of the US patent disclose methods wherein the surfactants are considered to be completely dissolved during the actual dry cleaning operation. Furthermore, these surfactants are liquid under the cleaning conditions used in these processes.

The US 5,858,022 relates to a method of dry cleaning articles in carbon dioxide, comprising: contacting an article to be cleaned with a liquid dry cleaning composition comprising a mixture of carbon dioxide, water, surfactant and an organic cosolvent; and thereafter separating the article from the liquid dry cleaning composition. The methods described in the examples use a cleaning composition in which the surfactants are completely dissolved during the cleaning process.

The US 6,200,352 describes a process for dry cleaning articles such as fabrics and clothing using a liquid dry cleaning composition comprising a mixture of carbon dioxide, a surfactant and an organic co-solvent. The preferred surfactant is one that does not contain a group with affinity for CO ₂ .

Dry cleaning systems using densified carbon dioxide known in the art suffer from the disadvantage that, although they can be effectively used to remove certain types of stains, they are unable to handle all types of stains including nonpolar stains (US Pat. for example, those made from a nonpolar organic component such as mineral oil, Pflan polar stains (for example, grape juice, coffee and tea stains), multi-component hydrophobic stains (for example, stains of lipstick and candle wax) and particulate soil (for example, stains involving insoluble solid components such as stains) For example, silicates, carbon black, etc. included) to remove.

The The present invention provides an improved dry cleaning process ready, the compressed carbon dioxide and a special surfactant The method offers the advantage of being used Can be effective to remove all kinds of stains from items such as Remove tissues.

SUMMARY OF THE INVENTION

The Inventors have surprisingly discovered that in a process for dry cleaning of articles with a compressed carbon dioxide composition the use an ionic surfactant, for example a surfactant that is a lipophilic Alkyl radical and an amine, sulfate, phosphate and / or Karboxylatrest according to claim 1 contains exceptionally good Cleaning results, if the surfactant used in an amount that will be its maximum solubility in the compressed carbon dioxide composition among those used Conditions during exceeds the cleaning process, and the surfactant provided during the cleaning process in the form of undissolved solid particles is present. It was unexpectedly found that the resulting Presence of unresolved allows ionic surfactant particles, effectively remove all types of stains, d. H. polar, non-polar, multi-component stains and especially particulate staining.

Even though the inventors do not want to be bound by theory, it is believed that the exceptionally good Results achieved with the present method, for Part in the ability the ionic surfactant particles are an electrostatic surface charge while of the washing process to be created and maintained, thereby allowing that these particles catch and bind dirt particles until the resulting Aggregates of the cleaned article together with the compacted one Carbon dioxide composition are removed. Thus, the reinforced Presence of a significant amount of undissolved ionic surfactant particles the cleaning effect of condensed carbon dioxide and dissolved ionic Surfactant.

DETAILED DESCRIPTION THE INVENTION

• a) In-Kontakt-Bringen des Artikels mit einer fluiden Trockenreinigungszusammensetzung, die verdichtetes Kohlendioxid bei einer Temperatur zwischen –20 und 60°C und einem Druck zwischen 1 und 100 Mpa enthält, um zu ermöglichen, dass sich Flecken lösen und/oder in die fluide Trockenreinigungszusammensetzung dispergieren und
• b) Auftrennen des Artikels und der fluiden Trockenreinigungszusammensetzung;

worin die fluide Trockenreinigungszusammensetzung ein ionisches Tensid in einer Konzentration zwischen 0,01 und 15 Gew.-% des Kohlendioxids umfasst und wobei während Schritt a) zumindest 10%, vorzugsweise zumindest 30% des ionischen Tensids in einer ungelösten festen Form vorliegen.Accordingly, the present invention relates to a method of dry cleaning an article comprising the sequential steps:

• a) contacting the article with a fluid dry cleaning composition containing densified carbon dioxide at a temperature between -20 and 60 ° C and a pressure between 1 and 100 Mpa to allow stains to dissolve and / or penetrate the Disperse fluid dry cleaning composition and
• b) separating the article and the fluid dry cleaning composition;

wherein the fluid dry cleaning composition comprises an ionic surfactant in a concentration between 0.01 and 15% by weight of the carbon dioxide and wherein during step a) at least 10%, preferably at least 30% of the ionic surfactant are in an undissolved solid form.

The here used term "ionic Surfactant " Surfactants used in the conditions used in step a) and according to the formulas in claim 1 either positively charged (cationic surfactants), negative charged (anionic surfactants) or zwitterions are.

The As used herein, "cleaning" refers to any Remove dirt, grime, soot or other unwanted Material, whether partial or complete. The present method can used to make non-polar spots, polar spots, multiple Components existing hydrophobic stains and particulate pollutions to clean. Examples of articles using the method according to the invention can be suitably cleaned, include tissues such. B. woven and non-woven fabrics made of materials such as Cotton, wool, silk, leather, viscose, polyester, acetate, fiberglass, Furs etc. were made. These tissues can become objects like for example, clothing, work gloves, cloths, leather goods (for example Handbags and briefcases) etc. be processed The present Procedure can also be used to clean items that no tissues are, such as semiconductors, electromechanical Micro devices, optoelectronics, fiber optics and machined or manufactured metal parts.

During the Purification process, the undissolved surfactant is in a solid Form, especially in the form of solid particles. It is noted that the present process also includes the use of surfactants which are liquid at room temperature and atmospheric pressure, however, these surfactants are solid particles before and / or during step a) form, for example as a result of a chemical or physical Interaction with other ingredients used in the cleaning composition available. For example, you can liquid Amine surfactants are suitably used in the present process, as they are during of the cleaning process to form solid particles, presumably as one Result of the reaction with carbon dioxide, which leads to the formation of a solid Carbamate leads.

Examples reactions that take place between amine surfactants, carbon dioxide and others Components of the fluid dry cleaning composition before and / or while Step a) take place and contribute to the formation of reaction products to lead could which precipitate as solid particles include:

Protonation of amines according to the following reactions [1-3]: CO ₂ + H ₂ O ↔ H ₂ CO ₃ (1) H ₂ CO ₃ + H ₂ O ↔ H ₃ O ⁺ + HCO ₃ ^- (2) R ₁ R ₂ NH + H ₃ O ⁺ ↔ R ₁ R ₂ NH ₂ ⁺ + H ₂ O (3) wherein R ₁ R ₂ NH is a primary or a secondary amine.

Primary and secondary amines can also react with carbon dioxide to form a zwitterion [5]: CO ₂ + R ₁ R ₂ NH ↔ R ₁ R ₂ NH ⁺ COO ^- (5)

This zwitterion is found in the isoelectric region. Above the isoelectric region, the zwitterion can be deprotonated by a base [6-8]: R ₁ R ₂ NH ⁺ COO ^- + R ₁ R ₂ NH ↔ R ₁ R ₂ NCOO ^- + R ₁ R ₂ NH ₂ ⁺ (6) R ₁ R ₂ NH ⁺ COO ^- + H ₂ O ↔ R ₁ R ₂ NCOO ^- + H ₃ O ⁺ (7) R ₁ R ₂ NH ⁺ COO ^- + HCO ₃ ^- ↔ R ₁ R ₂ NCOO ^- + H ₂ CO ₃ (8)

Below the isoelectric region of the zwitterion, the zwitterion can be protonated according to the following reaction [9]: R ₁ R ₂ NH ⁺ COO ^- + H ₃ O ⁺ ↔ R ₁ R ₂ NH ⁺ COOH + H ₂ O (9)

Around sufficient time available to make so that stains dissolve and / or can disperse into the dry cleaning fluid preferred that the duration of step a) one minute, especially preferably exceeds two minutes and most preferably five minutes.

The liquid Dry cleaning compositions useful for the practice of the present invention useful are usually included some water. The origin of the water is in all applications critical. The water may be the dry cleaning composition added before the items to be cleaned are placed in them, it can while added to the cleaning process or it can be water that is carried along with the garments or added to it before was etc.

In an embodiment The invention can be a better particulate cleaning by waiving on water addition to the dry cleaning composition. There is already water on or in the to be cleaned garments or articles when placed in the cleaning vessel become. The presence of a certain amount of water in one Tissue gives a specific swelling of the tissue from which one assumes that it is the tissue for makes the dry cleaning composition more accessible. The improved accessibility facilitates the removal of stains (especially oil and grease stains), which have penetrated into the interior of the tissue.

According to one preferred embodiment of the present method the fluid dry cleaning composition preferably less as 10% by weight of water. Most preferably, the composition contains less as 6 wt .-% water. Most preferably, the water content the dry cleaning composition is between 0.0001 and 5% by weight and Most preferably, the water content is in the range of 0.03-5 Wt .-%. Here, the water content refers to the total water content the composition, d. H. Water coming from different sources (for example the article) as described above.

In a preferred embodiment of the present process, in addition to carbon dioxide, one or more co-solvents are employed in the fluid dry cleaning composition. Suitable examples of these cosolvents are aliphatic and aromatic hydrocarbons and also esters and ethers thereof, in particular EXXON ISOPAR L, ISOPAR M, ISOPAR V, EXXON EXSOl, EXXON DF 2000, CONDEA VISTA LPA-170N, CONDEA VISTA LPA-210, cyclohexanone and Dimethyl succinate, alkyl and dialkyl carbonates (for example, dimethyl carbonate, dibutyl carbonate, di-t-butyl dicarbonate, ethylene carbonate and propylene carbonate), alkylene and polyalkylene glycols, and ethers and esters thereof (for example, ethylene glycol n-butyl ether, diethylene glycol n-butyl ether, propylene glycol methyl ether , Dipropylene glycol methyl ether, tripropylene glycol methyl ether and dipropylene glycol methyl ether acetate), lactones (for example gamma-butyrolactone, epsilon-caprolactone and delta-dodecalactone), alcohols and diols (2-methoxy-2-propanol, 1-octanol, 2-ethylhexanol, cyclopentanol, 1.3 Propanediol, 2,3-butanediol, 2-methyl-2,4-pentanediol) and polydimethylsiloxanes (for example, decamethyltetrasiloxane, decamethylpentasiloxane and hex amethyldisiloxane), etc. Particularly suitable cosolvents are C ₁ -C ₆ -alcohols (for example, methanol, ethanol, isopropanol, n-heptane, ethylene, propylene, benzene, toluene, p-xylene, sulfur dioxide, chlorotrifluoromethane, trichlorofluoromethane, perfluoropropane , Chlorodifluoromethane, sulfur hexafluoride and nitric oxide. The preferred co-solvent is a C ₁ -C ₆ alcohol or diol. The co-solvent is particularly preferably a C ₁ -C ₅ -alcohol. Most preferably, the co-solvent is a C ₂ -C ₄ -alcohol.

The previously listed Co-solvents are advantageously present in an amount of at least 0.1 Wt .-% of the dry cleaning composition used, especially preferably in an amount of 0.1-10% by weight.

As for the Person skilled in the art can numerous additional Ingredients in the present fluid dry cleaning composition be included, including Detergents, bleaches, whiteners, Plasticizers, embossing agents, Strengthen, Enzymes, hydrogen peroxide or a source of hydrogen peroxide, fragrances Etc.

The The present method suitably becomes about room temperature carried out. Therefore, in a preferred embodiment, the method comprises bringing into contact of the article with the fluid dry cleaning composition a temperature between 0 and 30 ° C. Equally includes in a preferred embodiment Step a) contacting the article with the fluid dry cleaning composition at a pressure between 2 and 25 MPa.

In In practice, in a preferred embodiment of the invention articles to be cleaned and the fluid dry cleaning composition brought together in a closed drum. The liquid dry cleaning composition is preferably provided in such an amount that the closed Drum both a liquid Phase as well as a vapor phase (i.e., that the drum is not Completely with the article and the liquid Filled composition is). The article is then stirred around in the drum, preferably such that the article with both the liquid dry cleaning composition as well as with the vapor phase comes into contact, the circulation of a sufficiently long time to clean the article. The cleaned article can then be removed from the drum.

Of the Article can after the recirculation step and before it is removed from the drum, if necessary, be rinsed (For example, by removing the composition from the drum, a rinse solution like for example, liquid Carbon dioxide (with or without additional Ingredients such as water, co-solvent, etc.) into the drum, the article is stirred in the rinse solution, the Rinse solution removed and the whole is repeated as desired). The dry cleaning compositions and the rinsing solutions can with any suitable means, including both Draining as well as venting.

In a particularly preferred embodiment of the invention, the present method comprises a rinsing step, wherein the original dry cleaning composition by a composition which contains condensed carbon dioxide and optionally further constituents, but no undissolved ionic surfactant. The latter composition can be advantageously used to remove any remaining undissolved surfactant. The flushing process with compressed carbon dioxide can be repeated several times accordingly. Preferably, the compressed carbon dioxide used in the flushing process contains a co-solvent, as defined above, and / or water, as such a co-solvent facilitates dissolution of the undissolved ionic surfactant and the water improves the removal of non-particulate contamination can.

each suitable cleaning device can be used, including a device with horizontal drum as well as one with vertical drum. If the drum is a horizontal drum becomes the recirculation step simply performed by a rotation of the drum. When the drum is a vertical drum, it is typically arranged with one inside agitator equipped, and the Umwälzungsschritt is carried out, by the agitator in the drum (for example, rotating or oscillating) moves. A vapor phase can be formed by providing adequate shear forces within the drum are applied to cavitation in the liquid dry cleaning composition to create.

Finally, in an alternative embodiment of the invention, the circulation can be carried out by means of a nozzle-driven stirring technique, as in US Pat U.S. Patent No. 5,467,492 by Chao et al. As noted previously, the fluid dry cleaning composition is preferably for use at ambient temperature, and the recirculating step is also preferably performed at room temperature so that the connection of a heating element to the cleaning device is unnecessary.

The The invention will be explained in more detail with reference to the following examples:

EXAMPLES

example 1

The Experiment is in a 25-liter jar with a 10-liter rotary drum carried out. The vessel points two sight glasses on to observe the behavior of the fluid. During the Cleaning and rinsing cycle rotates the drum alternately clockwise for 30 seconds and counterclockwise for 30 seconds each at one speed of 75 revolutions per minute. The dry cleaning fluid is passed through the vessel under Use of a centrifugal pump circulated. The pipe from the vessel to the pump contains a filter while the line from the pump to the vessel contains a heat exchanger to the temperature of the overall system. The equipment includes a mass flow meter, a temperature gauge and a pressure gauge.

During the cleaning cycle, the rotary drum is filled with 10 small pre-soiled test cloths. These contaminated test tissues are: SPOT TISSUE 1 Sebum and soot Wool 2 Sebum and soot polyester 3 egg yolk Wool 4 egg yolk polyester 5 Butterfat with colorant cotton 6 Butterfat with colorant Polyester / cotton blend 7 Vegetable oil with chlorophyll cotton 8th Vegetable oil with chlorophyll Polyester / cotton blend 9 Clay Wool 10 Clay polyester

The test fabrics were added to an additional load (400 g) of white cotton fabrics. The soiled test tissues were analyzed before and after the cleaning cycle to determine the change in tissue coloration. The values were expressed in laboratory values. The absolute color difference between two samples in the laboratory is expressed as:

In order to investigate the efficiency of cleaning, both the cleaned and soiled fabrics are compared with the original unpolluted fabric, resulting in the absolute color differences ΔE _{soiled-unpolluted} and ΔE _{cleaned-unpolluted} . The purification efficiency index of an experiment is expressed as:

If the fabric is clean, the CPI _Lab value is 100%; if the cleaning has no effect, the value is 0%.

The Cleaning is started by placing the vessel in room conditions with the additional Loading and the attached filled contaminated test fabrics becomes. Subsequently was a cleaning fluid containing 250 g of isopropanol, 25 g of water and 39 g dissolved Dodecylamine contained, added to the fabric charge. The vessel was closed and with 6 kg of liquid Carbon dioxide pressurized from a storage tank. The system reached a pressure of 48 bar and a temperature of 12 ° C. By The viewing window was observed to be a large amount small particle formed. The particles were collected and analyzed. It was found that the material in the particles one Melting point, the approximately 20 ° C higher as the melting point of dodecylamine.

The rotary drum was started and the tissue was cleaned for 30 minutes. After cleaning, the vessel was purged with 12 kg of fresh carbon dioxide from the storage tank for 10 minutes while maintaining the system at 48 bar. Thereafter, the vessel was depressurized, whereupon it opened, the cleaned tissues were taken out and the color differences were measured. The CPI _Lab values obtained are listed in the table below.

Example 2

Example 1 was repeated with the difference that the cleaning fluid was now composed of 250 g iso-propanol, 25 g water and 40 g dioctylamine. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 48 bar and a temperature of 12 ° C. Through the sight glasses, it was observed that a large amount of small particles formed. After purification, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are listed in the table below.

Example 3

Example 1 was repeated with the difference that this time 50 g of solid sodium stearate and 25 g of water were added to the cleaning vessel. The vessel was sealed and pressurized with 4 kg of liquid carbon dioxide from a storage container. The system reached a pressure of 46 bar and a temperature of 10 ° C. It was observed through the sight glass that a large amount of sodium stearate was not dissolved in the carbon dioxide. After purification, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are listed in the table below.

Example 4

Example 1 was repeated with the difference that this time 10 g of solid sodium dodecyl sulfate and 25 g of water were added to the cleaning vessel. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 46 bar and a temperature of 11 ° C. It was observed through the sight glass that a large amount of sodium dodecyl sulfate was not dissolved in the carbon dioxide. After purification, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are listed in the table below.

Example 5 (Reference example, not according to the invention)

Example 1 was repeated with the difference that the cleaning fluid was composed of 250 g of isopropanol, 25 g of water and 1 g of tribenzylamine. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 45 bar and a temperature of 10 ° C. Through the sight glass, it was observed that a large amount of small particles formed. After purification, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are listed in the table below.

Example 6

Example 1 was repeated with the difference that the cleaning fluid from 255 g of iso-propanol, 25 g of water and 1 g of octadecylamine was composed. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 48 bar and a temperature of 12 ° C. Through the viewing window was observed that formed small particles. After cleaning, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are shown in the table below.

Example 7

Example 6 was repeated except that the cleaning fluid was composed of 251 g of iso-propanol, 25 g of water and 5 g of octadecylamine. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 46 bar and a temperature of 11 ° C. Through the sight glass it was observed that small particles formed. After cleaning, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are shown in the table below.

Example 8

Example 6 was repeated with the difference that the cleaning fluid was composed of 250 g of iso-propanol, 25 g of water and 10 g of octadecylamine. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 48 bar and a temperature of 12 ° C. Through the sight glass, it was observed that a substantial amount of small particles formed. After cleaning, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are shown in the table below.

Example 9

Example 6 was repeated with the difference that the cleaning fluid was composed of 250 g of iso-propanol, 30 g of water and 40 g of octadecylamine. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 46 bar and a temperature of 11 ° C. Through the sight glass, it was observed that a large amount of small particles formed. After purification, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are listed in the table below.

Example 10

Example 1 was repeated except that the cleaning fluid was composed of 250 g of iso-propanol and 10 g of N-lauroyl-L-lysine. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The system reached a pressure of 57 bar and a temperature of 20 ° C. Through the sight glass, it was observed that a large amount of small particles formed. After purification, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are listed in the table below.

Example 11

Example 1 was repeated except that the cleaning fluid was composed of 250 g of iso-propanol and 5 g of N-lauroyl-L-lysine. The vessel was closed and with 6 kg of liquid Koh lendioxid from a storage container pressurized. The system reached a pressure of 52 bar and a temperature of 16 ° C. Through the sight glass, it was observed that a large amount of small particles formed. After cleaning, the vessel was rinsed with pure carbon dioxide and depressurized as described in Example 1. Then, the fabric charge was added to a rinse fluid containing 250 g of iso-propanol and 25 g of water. The vessel was closed and pressurized with 6 kg of liquid carbon dioxide from a storage tank. The rotary drum was started and the fabric was rinsed for 30 minutes. After this rinsing step, the vessel was rinsed again with pure carbon dioxide and depressurized as described in Example 1.

Comparative Example A

Example 1 was repeated with the difference that no cleaning liquid was introduced into the vessel. The vessel was closed and pressurized with 12 kg of liquid carbon dioxide from a storage container. The system reached a pressure of 45 bar and a temperature of 10 ° C. After purification, the vessel was rinsed and depressurized as described in Example 1. The CPI _Lab values obtained for each test tissue are listed in the table below.

The purification efficiency (expressed as CPI _Lab values) obtained in the respective cleaning cycles of the examples listed above is summarized in the following table: Examples 1 2 3 4 5 6 7 8th 9 10 11 A Sebum on wool 74 76 63 58 44 55 57 79 89 71 72 30 Sebum on polyester 46 44 44 40 23 36 42 48 58 49 56 21 Egg yolk on wool 64 62 46 47 56 60 60 62 64 44 56 41 Egg yolk on polyester 50 55 40 38 49 51 48 49 53 40 39 37 Butterfat on cotton 80 90 72 62 88 84 86 86 84 75 91 65 Butterfat on mixed fabric 87 93 83 76 92 89 89 90 87 83 94 80 Vegetable oil on cotton 57 67 41 27 64 55 51 61 65 49 54 16 Vegetable oil on blended fabric 20 20 27 19 26 22 15 24 23 22 20 6 Clay on wool 68 62 52 66 32 43 35 44 47 71 83 13 Clay on polyester 12 11 27 39 2 13 9 2 12 16 17 1

The The above results show that the addition of an ionic surfactant the cleaning efficiency dramatically improved. Examples 1, Figures 2, 3, 4, 9, 10 and 11 illustrate that the benefits of the present invention Invention achieved with different types of ionic surfactants although the improved cleaning efficiency is improved manifest in different ways. The results have also shown that the amines are particularly effective. The examples 6, 7, 8 and 9 show that an increase in the surfactant concentration increases the cleaning efficiency of the wash cycle. This is a surprising Discovery because the amount of dissolved surfactant applied in all these examples the same is. All examples show that especially the removal particulate Pollution is dramatically improved.

Claims (10)

A process for dry cleaning an article, especially a fabric, comprising the sequential steps of: a) contacting the article with a fluid dry cleaning composition containing compressed carbon dioxide at a temperature between -20 and 60 ° C and a pressure between 1 and 100 MPa to allow stains to dissolve and / or disperse into the fluid dry cleaning composition; and b) separating the article and the fluid dry cleaning composition; wherein the fluid dry cleaning composition comprises an ionic surfactant in a concentration of between 0.01 and 15% by weight of the carbon dioxide and wherein during step a) at least 10%, preferably at least 30% of the ionic surfactant are in an undissolved solid form; wherein the ionic surfactant is represented by the formula R ₁ X, XR ₁ X or R ₂ YR _2; wherein: R _{1 is} a substituted or unsubstituted, linear or branched, optionally heterogeneous C ₁ -C ₂₂ alkyl; a substituted or unsubstituted, optionally heterogeneous C ₃ -C ₁₆ cycloalkyl; a substituted or an unsubstituted, linear or branched, optionally heterogeneous C ₁ -C ₂₂ alkenyl; or a substituted or unsubstituted, optionally heterogeneous aryl; R ₂ and R _{2 are} independently R ₁ , X ₁ , R _{a is} X or R _{a is} (X) ₂ ; R _{a represents} a substituted or unsubstituted, linear or branched, optionally heterogeneous C ₁ -C ₂₂ -alkyl, a substituted or unsubstituted, optionally heterogeneous C ₃ -C ₁₆ -cycloalkyl; a substituted or unsubstituted, linear or branched, optionally heterogeneous C ₁ -C ₂₂ alkenyl; or a substituted or unsubstituted, optionally heterogeneous aryl; and X is NH ₂ , NH ₃ ⁺ , COOM ₁ , COO ^- , OP (O) (OM ₁ ) (OM ₂ ), OS (O) ₂ (OM ₁ ); Y is NH; and M ₁ and M ₂ independently represent sodium, potassium, ammonium or hydrogen. The method of claim 1, wherein the duration of the step a) lasts more than 1 minute, preferably 2 minutes. The method of claim 1 or 2, wherein the method a rinse step wherein the fluid dry cleaning composition comprises a rinse composition, the compressed carbon dioxide, but no undissolved ionic surfactant contains replaced becomes. The method of claim 3, wherein the rinse composition contains a co-solvent and / or water. The process of claim 1 wherein X is NH ₂ and / or COOM ₁ and Y is NH. The process of claim 1 wherein R ₁ and R _{a are} independently a substituted or unsubstituted, linear or branched, optionally heterogeneous C ₃ -C ₂₂ alkyl, or a substituted or unsubstituted, linear or branched, optionally heterogeneous C ₃ -C ₂₂ alkenyl are. A method according to any one of claims 1-6, wherein the fluid dry cleaning composition contains between 0.0001 and 5 wt .-% water. A method according to any one of claims 1-7, wherein the fluid dry cleaning composition contains a co-solvent, selected from the group consisting of aliphatic and aromatic hydrocarbons as well Esters and ethers thereof, alkyl and dialkyl carbonates, alkylene and polyalkylene glycols and ethers and esters thereof, lactones, Alcohols and diols, polydimethylsiloxanes and combinations thereof consists. The method of any of claims 1-8, wherein step a) is in contact of the article with the fluid dry cleaning composition a temperature between 0 and 30 ° C includes. The method of any one of claims 1-10, wherein step a) is in contact of the article with the fluid dry cleaning composition a pressure between 2 and 25 MPa.