Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/02—Inorganic compounds ; Elemental compounds
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/395—Bleaching agents
  • C11D3/3953—Inorganic bleaching agents
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/395—Bleaching agents
  • C11D3/3956—Liquid compositions
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/43—Solvents
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
  • D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
  • D06L4/10—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen
  • D06L4/13—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen using inorganic agents
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
  • D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
  • D06L4/10—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen
  • D06L4/17—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen in an inert solvent
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
  • D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
  • D06L4/20—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which contain halogen
  • D06L4/22—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which contain halogen using inorganic agents
  • D06L4/23—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which contain halogen using inorganic agents using hypohalogenites
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
  • D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
  • D06L4/20—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which contain halogen
  • D06L4/22—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which contain halogen using inorganic agents
  • D06L4/24—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which contain halogen using inorganic agents using chlorites or chlorine dioxide

Definitions

• the present invention relates to the field of bleaching compositions to remove stains from articles, in particular textile articles.
• the present invention relates to a method of preparing a bleaching composition and method to bleach articles.
• US-A-5 431 843 discloses a perhydrolysis system for use in condensed fluid medium for bleaching of stained garments.
• This perhydrolysis system comprises two essential components: hydrogen peroxide and an organic peracid precursor.
• the examples seem to indicate that a combination of hydrogen peroxide and nonanoyloxyglycoylphenyl sulfonate (NOGPS) results in a better overall stain removal when compared to hydrogen peroxide alone. To obtain these results, the bleaching process takes place for at least 1 hour.
• US-A-5 676 705 describes the use of organic peracid precursor in a dry cleaning process using carbon dioxide.
• both the preformed peracids and the directly added organic peracid precursor should be soluble in densified carbon dioxide.
• inorganic bleaching agents for removal of soil from garments in aqueous systems has been known for a long time.
• US-A-3 332 882 teaches the use of bleaches in combination with triazine activators.
• US-A-4 300 897 teaches a method of bleaching using peroxomonosulfate-based compositions.
• WO-A-9923197 teaches a process of soaking fabrics with a liquid aqueous persulfate salt-containing composition.
• WO-A-9921950 teaches the use of peroxonitrite based bleaching systems.
• inorganic bleaching agent could be effective in a bleaching method wherein the medium is mainly carbon dioxide.
• organic peracids and/or precursor systems are generally effective they still exhibit several disadvantages. For example, these organic compounds are moderately sophisticated molecules requiring multi-step manufacturing processes resulting in high capital costs. Also, these precursor systems have large formulation space requirements as they also need addition of hydrogen peroxide and/or a hydrogen peroxide delivery system. Consequently, a significant proportion of the cleaning formulation must be devoted to the bleach components, leaving less room for other active ingredients and complicating the development of concentrated formulations. Moreover, organic precursor systems do not bleach very efficiently in situations wherein short bleach times are desired and processing environment is acidic or pH neutral.
• an object of the invention to provide an alternative bleaching composition and method of bleaching which shows effective stain removal but does not display one or more of these drawbacks when applied in a bleaching process.
• One particular object of the invention is to provide a bleaching composition and a bleaching method which are economical and require short bleach times.
• Another object of the invention is to provide a bleaching composition and a method of bleaching which are particularly suitable for removing grass, tea and blackcurrant stains.
• inventive bleaching composition and method of bleaching which are substantially free of organic peracid and precursors thereof and still show a remarkably effective stain removal.
• a bleaching composition comprising
• a method to bleach articles comprising the following steps:
• the inventive composition and method is suitable to bleach articles in less than 45 min.
• the present invention is particularly advantageous for bleaching methods that require a short period of time.
• US-A-5 431 843 describes bleaching times of 1 hour for effective stain removal.
• the present invention provides effective bleaching in 45 minutes or less.
• Another advantage of the present invention is the simplicity. Without wishing to be bound by any theory it is believed that precursors only at high pH can form organic peracids effectively by perhydrolysis of the precursor. Since carbon dioxide has a low pH, special measures have to be taken to ensure the formation of relatively unstable peracids in a separate premix process. Furthermore, it is believed that the low temperatures used in carbon dioxide cleaning will also slow this reaction. Yet another advantage of the present invention is that it is remarkably effective on a variety of stains, especially grass, tea and black currant stains. The present invention is especially suitable to bleach and clean garments but may also be employed to bleach articles with hard surfaces.
• composition used in the inventive bleaching method should be essentially free of organic peracid and precursor thereof.
• "essentially free” means that if present, these (trace) amounts of organic peracid or precursor should be so low that these compounds do not significantly contribute to the bleaching effect compared to an identical bleaching composition free of said compounds. Preferably these trace amounts should contribute less than 25%, more preferably less than 10% even more preferably less than 5% to the bleaching effect.
• CS-8 ex CFT
• the bleaching composition is defined as the composition wherein the actual bleaching occurs analogous to a wash liquor.
• this bleaching composition may be prepared by adding a bleaching product to the carbon dioxide analogous to adding a detergent product to the wash liquor.
• organic peracid and precursors thereof are defined as compounds consisting from at least one carbon atom, excluding (per)hydrates of carbon dioxide and metal salts thereof.
• Inorganic bleaching agent is defined as a bleaching agent being not an organic peracid or precursor thereof.
• hydrogen peroxide per se is not an inorganic bleaching agent.
• the inorganic bleaching agent used in the present invention is selected from the group including peroxosulfates, peroxocarbonates, peroxoborates, peroxophosphates, peroxosilicates, chlorites, hypochlorites, peroxonitrites, and Na 2 O 2 , ZnO 2 , KO 2 , CaO 2 and mixtures thereof.
• the inorganic bleaching agent is selected from the group including peroxosulfates, peroxophosphates, peroxonitrites, chlorites, hypochlorites and mixtures thereof.
• Preferred salts of these inorganic bleaching agents comprise positive ions including alkali metal and earth alkali metal ions.
• the inorganic bleaching agent is selected from the group including peroxosulfates, peroxonitrites, chlorites, hypochlorites and mixtures thereof.
• Particularly preferred inorganic bleaching agents include alkali metal salts and alkali-earth metal salts of peroxomonosulfate, peroxonitrite, hypochlorite, chlorite and mixtures thereof.
• a bleach-effective amount of an inorganic bleaching agent is dispersed or dissolved into water.
• the exact amount will depend on the volume of carbon dioxide, number of articles and nature and quantity of stains. The skilled person will be able to determine the bleach-effective amount without undue burden.
• the inorganic bleaching agent is present in the bleaching composition from 0.01 to 50 mM, more preferably, from 0.05 to 20 mM and even more preferably from 0.1 to 10 mM.
• the bleaching agent may have any form known in the art.
• the form e.g., crystal, powder, granulate
• Preferred forms are those that easily dissolve or disperse in the bleach-compatible solvent.
• One preferred form is a particulate form wherein a particle size is chosen to obtain a good compromise between storage stability and convenient dissolution characteristics.
• Some inorganic bleaching agents such as sodium hypochlorite are commercially available as solutions and may also me used in present invention.
• peroxosulfate especially peroxomonosulfate.
• Suitable peroxosulfate salts include any alkali metal peroxosulfate salt including sodium peroxosulfate salts and/or potassium peroxosulfate salts.
• Preferred peroxosulfate salt to be used herein is the monopersulfate salt.
• One of the most preferred inorganic bleaching agents for the present invention is a water soluble peroxomonosulfate, normally an alkali metal peroxomonosulfate, such as potassium or sodium peroxomonosulfate.
• Potassium peroxomonosulfate KHSO5
• KHSO5 Potassium peroxomonosulfate
• 2KHSO5.KHSO4.K2SO4 sold by E. I. DuPont DeNemours and Company, Inc. under the trademark OxoneTM.
• That product has an active oxygen content of about 4.5%.
• the active oxygen content of the mixed salt described is about 5.2% when the salt is pure and the corresponding active oxygen content of KHSO5 is about 10.5%.
• the pure mixed salt has half as much active oxygen in it as has the pure peroxomonosulfate and the 86.5% pure mixed salt (OxoneTM) has 43% as much.
• the single salt is intended, with its higher active oxygen content, but an equivalent proportion of the triple salt, such as that sold under the trademark Oxone, will normally be employed as the source of the active bleaching compound because of its ready availability, stability and desirable physical characteristics.
• Potassium peroxomonosulfate may also be named as potassium monopersulfate and its triple salt may also be considered to be a monopersulfate compound within the context of this invention.
• monopersulfate salts commercially available are those commercialised by Interox under the trade name CuroxTM, by Degussa under the trade name CaroatTM or by DuPont under the trade name OxoneTM. It is to be understood herein that when the commercially available CuroxTM, CaroatTM and/or OxoneTM are used, the % weights or molar amounts of peroxosulfate salts mentioned herein, refer to the total weight of said CuroxTM, CaroatTM and/or OxoneTM.
• the active concentration is approximately 1/2 of the total weight.
• peroxosulfate salts such as dipersulfate salts commercially available among others from Peroxide Chemie GMBH can be used in the compositions according to the present invention.
• Another suitable persulphate salt is ammonium persulphate.
• the bleach composition according the invention comprises a surfactant.
• a surfactant Any surfactant known to the person skilled in the art may be used.
• Surfactants are described in US-A-5,789,505, US-A-5,683,977, US-A-5,683,473, US-A-5,858,022 and WO 96/27704.
• WO 96/27704 formsula's I-IV.
• n and m are each independently 1-35.
• Such functional groups (R n -) include halocarbons, polysiloxanes and branched polyalkylene oxides.
• denotesified carbon dioxide-phobic in reference to surfactants, R n Z m , means that Z m - will have a solubility in carbon dioxide of less than 10 weight percent at pressures of from 101 kPa to 68.9 MPa and temperatures of from -78.5 to 100°C.
• the functional groups in Z m - include carboxylic acids, phosphatyl esters, hydroxyls, C 1-30 alkyls or alkenyls, polyalkylene oxides, branched polyalkylene oxides, carboxylates, C 1-30 alkyl sulfonates, phosphates, glycerates, carbohydrates, nitrates, substituted or unsubstituted aryls and sulfates.
• the hydrocarbon and halocarbon containing surfactants i.e., R n Z m , containing the CO 2 -philic functional group, R n -, and the CO 2 -phobic group, Z m -
• R n Z m containing the CO 2 -philic functional group, R n -, and the CO 2 -phobic group, Z m -
• R n Z m may have an HLB of less than 15, preferably less than 13 and most preferably less than 12.
• the polymeric siloxane containing surfactants, R n Z m also designated MD x D* y M, with M representing trimethylsiloxyl end groups, D x as a dimethylsiloxyl backbone (CO 2 -philic functional group) and D* y as one or more substituted methylsiloxyl groups substituted with CO 2 -phobic R or R' groups preferably have a D x D* y ratio of greater than 0.5:1, preferably greater than 0.7:1 and most preferably greater than 1:1.
• a “substituted methylsiloxyl group” is a methylsiloxyl group substituted with a CO 2 -phobic group R or R'.
• R or R' are each represented in the following formula: -(CH 2 ) a (C 6 H 4 ) b (A) d - [(L) e (A') f ] n - (L') g Z(G) h wherein a is 1-30, b is 0-1, C 6 H 4 is substituted or unsubstituted with a C 1-10 alkyl or alkenyl and A, d, L, e, A', F, n L', g, Z, G and h are defined below, and mixtures of R and R'.
• a "substituted aryl” is an aryl substituted with a C 1-30 alkyl, alkenyl or hydroxyl, preferably a C 1-20 alkyl or alkenyl.
• a “substituted carbohydrate” is a carbohydrate substituted with a C 1-10 alkyl or alkenyl, preferably a C 1-5 alkyl.
• the terms "polyalkylene oxide”, “alkyl” and “alkenyl” each contain a carbon chain which may be either straight or branched unless otherwise stated.
• a preferred surfactant which is effective for use in a carbon dioxide bleach composition requires the combination of densified carbon dioxide-philic functional groups with densified carbon dioxide-phobic functional groups (see definitions above).
• the resulting compound may form reversed micelles with the CO 2 -philic functional groups extending into a continuous phase and the CO 2 -phobic functional groups directed toward the centre of the micelle.
• the surfactant is preferably present in an amount of less than 10 wt% or more preferably of from 0.001 to 10 wt%, preferably 0.01 to 5 wt%.
• An especially preferred range is from about 0.03% to about 1 wt%.
• the CO 2 -philic moieties of the surfactants are preferably groups exhibiting low Hildebrand solubility parameters, as described in Grant, D. J. W. et al. "Solubility Behavior of Organic Compounds", Techniques of Chemistry Series, J. Wiley & Sons, NY (1990) pp. 46-55 which describes the Hildebrand solubility equation, herein incorporated by reference.
• These CO 2 -philic moieties also exhibit low polarisability and some electron donating capability allowing them to be solubilised easily in densified fluid carbon dioxide.
• the CO 2 -philic functional groups are soluble in densified carbon dioxide to greater than 10 weight percent, preferably greater than 15 weight percent, at pressures of from 101 kPa to 68.9 MPa and temperatures of from -78.5 to 100°C.
• Preferred densified CO 2 -philic functional groups include halocarbons (such as fluoro-, chloro- and fluoro- chlorocarbons), polysiloxanes and branched polyalkylene oxides.
• the CO 2 -phobic portion of the surfactant molecule is obtained either by a hydrophilic or a hydrophobic functional group which is less than 10 weight percent soluble in densified CO 2 , preferably less than 5 wt. %, at a pressures of from 101 kPa to 68.9 MPa and temperatures of from -78.5 to 100°C.
• moieties contained in the CO 2 -phobic groups include polyalkylene oxides, carboxylates, branched acrylate esters, C 1-30 hydrocarbons, aryls which are unsubstituted or substituted, sulfonates, glycerates, phosphates, sulfates and carbohydrates.
• Especially preferred CO 2 -phobic groups include C 2-20 straight chain or branched alkyls, polyalkylene oxides, glycerates, carboxylates, phosphates, sulfates and carbohydrates.
• Preferred surfactants comprise CO 2 -philic and CO 2 -phobic groups.
• the CO 2 -philic and CO 2 -phobic groups are preferably directly connected or linked together via a linkage group.
• Such groups preferably include ester, keto, ether, amide, amine, thio, alkyl, alkenyl, fluoroalkyl, fluoroalkenyl and mixtures thereof.
• a preferred surfactant is:
• the surfactant when R of the surfactant is the halocarbon or the branched polyalkylene oxide, then the surfactant has an HLB value of less than 15. In other cases it may be preferred that when R is the polysiloxane, then the surfactant has a ratio of dimethyl siloxyl to substituted methyl siloxy groups of greater than 0.5:1.
• Surfactants which are useful in the invention may be selected from four groups of compounds ( forumula I-IV).
• the first group of compounds has the following formula: [(CX 3 (CX 2 ) a (CH 2 ) b ) c (A) d --[(L) e --(A') f ] n --(L') g ] o Z(G) h wherein X is F, Cl, Br, I and mixtures thereof, preferably F and Cl;
• Preferred compounds within the scope of the formula I include those having linking moieties A and A' which are each independently an ester, an ether, a thio, a polyalkylene oxide, an amido, an ammonium and mixtures thereof; L and L' are each independently a C 1-25 straight chain or branched alkyl or unsubstituted aryl; and Z is a hydrogen, carboxylic acid, hydroxyl, a phosphato, a sulfonyl, a sulfate, an ammonium, a polyalkylene oxide, or a carbohydrate, preferably unsubstituted.
• G groups which are preferred include H + , Li + , Na + , NH + 4 , Cl - , Br - and tosylate.
• Most preferred compounds within the scope of formula I include those compounds wherein A and A' are each independently an ester, ether, an amido, a polyoxyalkylene oxide and mixtures thereof; L and L' are each independently a C 1-20 straight chain or branched alkyl or an unsubstituted aryl; Z is a hydrogen, a phosphato, a sulfonyl, a carboxylic acid, a sulfate, a poly(alkylene oxide) and mixtures thereof; and G is H + , Na + or NH 4 + .
• fluorinated compounds include compounds supplied as the ZonylTM series by Dupont.
• the second group of surfactants useful in the bleach composition are those compounds having a polyalkylene moiety and having a formula (II).
• R and R' are each independently a hydrogen, a C 1-3 alkyl, or alkylene oxide and mixtures thereof.
• R and R' are each independently a hydrogen, C 1-3 alkyl and mixtures thereof.
• R and R' are each independently a hydrogen, C 1-3 alkyl and mixtures thereof.
• Non-limiting examples of compounds within the scope of formula II are described in WO 96/27704 Compounds of formula II may be prepared as is known in the art and as described in March et al., Supra.
• Examples of commercially available compounds of formula II may be obtained as the Pluronic series from BASF, Inc.
• a third group of surfactants useful in the invention contain a fluorinated oxide moiety and the compounds have a formula: [(CX 3 (XO) r (T) s ) c (A) d -[(L) e -(A') f -] n (L') g ) o Z(G) h
• Examples of commercially available compounds within the scope of formula III include those compounds supplied under the KrytoxTM series by DuPont having a formula: wherein x is 1-50.
• the fourth group of surfactants useful in the invention include siloxanes containing surfactants of formula IV MD x D* y M
• the D x :D* y ratio of the siloxane containing surfactants should be greater than 0.5:1, preferably greater than 0.7:1 and most preferably greater than 1:1.
• the siloxane compounds should have a molecular weight ranging from 100 to 100,000, preferably 200 to 50,000, most preferably 500 to 35,000.
• Silicones may be prepared by any conventional method such as the method described in Hardman, B. "Silicones” the Encyclopaedia of Polymer Science and Engineering, v. 15, 2nd Ed., J. Wiley and Sons, NY, NY (1989).
• siloxane containing compounds which may be used in the invention are those supplied under the ABIL series by Goldschmidt.
• Suitable siloxane compounds within the scope of formula IV are compounds of formula V:
• Preferred CO 2 -phobic groups represented by R and R' include those moieties of the following formula: (CH 2 ) a (C 6 H 4 ) b (A) d -[(L) e -(A') f -]-(L') g Z(G) h
• Particularly useful surfactants are selected from the group consisting of the classes of ethoxy modified polydimethylsiloxanes (e.g. SilwetTM surfactants from Witco), acetylenic glycol surfactants (from Air Products) and ethoxy/propoxy block copolymers (e.g. PluronicTM surfactants from BASF) and mixtures thereof.
• SilwetTM surfactants from Witco
• acetylenic glycol surfactants from Air Products
• PluronicTM surfactants from BASF
• the inventive bleach composition also comprises a bleach-compatible solvent.
• the type of solvent will depend on the exact nature of the bleaching agent. If the bleaching agent is more or less hydrophobic then a hydrophobic fluid may be preferred. Alternatively if the organic substance is more or less hydrophilic, a hydrophilic fluid may be preferred. In many cases it will be preferable, to dissolve or to disperse bleaching agent in an aqueous solvent such as water.
• Preferred amounts of bleach-compatible solvent should be from 0.0001 to about 10 wt% (weight/weight of the carbon dioxide), more preferably 0.001 to about 5 wt%, even more preferably 0.01 to about 3 wt%, most preferably from about 0.05 to about 0.2 wt%.
• Preferred solvents include water, ethanol, acetone, hexane, methanol, glycols, acetonitrile, C 1-10 alcohols and C 5-15 hydrocarbons. Especially preferred solvents include water, ethanol and methanol.
• a modifier in the bleaching composition such as water, or an organic solvent up to only about 10 wt% ,and additives to boost the bleaching and or cleaning performance such as enzymes up to about 10 wt%, surfactants, perfumes, and antistats.
• a modifier such as water, or a useful organic solvent may be added with the stained cloth in the cleaning drum in a small volume.
• Preferred amounts of modifier should be from 0.0 to about 10 wt% (weight/weight of the CO 2 ), more preferably 0.001 to about 5 wt%, even more preferably 0.01 to about 3 wt%, most preferably from about 0.05 to about 0.2 wt%.
• Preferred solvents include water, ethanol, acetone, hexane, methanol, glycols, acetonitrile, C 1-10 alcohols and C 5-15 hydrocarbons.
• Especially preferred solvents include water, ethanol and methanol.
• the modifier is water, optionally 0.1 to 50% of an additional organic cosolvent may be present as described in US-A-5 858 022. In those circumstances it may be preferred to use surfactants as described in US-5 858 022 which do contain a CO2 philic group.
• the method to prepare the inventive composition is characterised in that said method comprises the steps of
• the compatibility of the solvent will depend on the exact nature of the bleaching agent as indicated above. In many cases it will be preferable, to dissolve or to disperse the bleaching agent in an aqueous solvent.
• a particularly preferred solvent is water. Usually the best results are achieved when substantially most of the bleaching agent is dissolved although in some cases some of the bleaching agent may still be dispersed. In contrast to organic precursors such as TAED, we have found that inorganic bleaching agents as peroxomonosulphate dissolve very quickly in water. In many cases, it will be preferred to dissolve or disperse the bleaching agent immediately prior to the bleaching process because the dissolved bleach may not be stable.
• the bleaching agent is mixed with the solvent for less than 5 min, more preferably less than 3 min, even more preferably less than 1 min immediately prior to mixing the bleaching agent with the carbon dioxide.
• some inorganic bleaches may be conveniently purchased as stable solutions for example, hypochlorite. It is to be understood that the use of such solutions of bleaching agents is also encompassed in the inventive method of preparing the bleaching composition.
• the advantage of the inorganic bleaching agent used in the present invention is that it usually dissolves rapidly without the need to adjust the pH.
• the inorganic bleaching agent is mixed with pH neutral solvent such as water.
• the inventive bleaching method may be used in cleaning systems with carbon dioxide such as described in US-A-5 683 473, US-A-5 676 705, US-A-5 683 977, US-5 881 577, US-A-5 158 704, US-A-5 266 205, US-A-5 858 022 and the references cited therein.
• an effective dry cleaning amount of densified carbon dioxide is used.
• the exact amount will depend on the volume of the vessel, pressure at which the dry cleaning is performed, number of articles and nature and quantity of stains.
• the skilled person will be able to determine effective dry cleaning amount of densified carbon dioxide without undue burden using the references above.
• the amount of carbon dioxide will correspond to a volume of from 0.1 and 500 litre, more preferably of from 0.2 to 100 litre at the operating pressure and temperature.
• the bleaching method may be used to bleach and/or clean any suitable article.
• the items to be cleaned should be compatible with the carbon dioxide.
• the items include garments and domestic articles with hard surfaces.
• the bleaching method is especially useful to clean textile articles with bleachable stains, in particular those with grass stains.
• the method to bleach articles is characterised in that said method comprises the following steps:
• the method of bleaching comprises loading a variety of soiled articles, preferably clothing, into a vessel (preferably a pressurisable vessel) and contacting the articles with the bleaching composition comprising the inorganic bleaching agent.
• the bleaching composition minus the carbon dioxide may be contacted with the soiled articles before or together with the carbon dioxide.
• the carbon dioxide may be introduced into the cleaning vessel as described in US-A-5,683,473.
• the carbon dioxide is introduced into the cleaning vessel which is then pressurised to a pressure in the range of about 0.1 to about 68.9 MPa and adjusted to a temperature range of from about -78.5°C up to about 100°C.
• the bleaching method may be carried out in supercritical carbon dioxide where the temperature is between 31°C and 100°C, preferably between 31°C and 60°C. Often it is preferred that the carbon dioxide is in a liquid phase so the temperature is held at - 78.5°C up to about 30°C.
• the pressure range is from 0.5 to 48 MPa, more preferably from 2.1 to 41 MPa.
• the temperature range is from -56.2 to 25°C, more preferably from -25°C to 20°C.
• densified molecules having supercritical properties may also be employed alone or in mixture. These molecules include methane, ethane, propane, ammonia, butane, n-pentane, n-hexane, cyclohexane, n-heptane, ethylene, propylene, methanol, ethanol, isopropanol, benzene, toluene, p-xylene, sulfur dioxide, chlorotrifluoromethane, xenon trichlorofluoromethane, perfluoropropane, chlorodifluoromethane, sulfur hexafluoride and nitrous oxide.
• one of the advantages of the present invention is that very short bleaching times are needed to obtain good bleaching.
• the articles are contacted with the bleaching composition for less than 45 min, more preferably less than 35 min, most preferably less 25 min.
• the inventive bleaching method may be used in densified carbon dioxide although in some case liquid carbon dioxide may be preferred.
• bleach sensitive test cloths BC-1, CS-8 and CS-12 were dry cleaned using liquid carbon dioxide, hydrogen peroxide, inorganic bleaching agents and mixtures thereof according to the invention.
• BC-1 is a tea stained test cloth
• CS-8 is a grass stained test cloth
• CS-12 is a black currant stained test cloth; all are made by CFT.
• Four 2" X 2" swatches of a given stain cloth were placed in a 600 ml autoclave having a gas compressor, an extraction system and a stirrer. The cloths were allowed to move freely in the autoclave. Good agitation was ensured by visual observation with an endoscope through a small sapphire window in the autoclave.
• liquid CO 2 at a tank pressure of 5.86 Mpa was allowed into the system and was cooled to reach a temperature of about 12°C at which point the liquid CO 2 was at a pressure of about 5.52 MPa.
• the stirrer was then turned on for 15 minutes to mimic a wash cycle.
• 20 cubic feet of fresh CO 2 were passed through the system to mimic a rinse cycle.
• the pressure of the autoclave was then released to atmospheric pressure and the cleaned cloths were removed from the autoclave. Two runs were performed with each system tested. To measure the extent of cleaning, the cloths were placed in a Reflectometer supplied by Colorguard.
• Bleaching results on the stained cloths are shown in Table 1 below. Bleach Results using Caroat (Peroxosulfate Bleaching agent) at 2mM Bleach Composition % Soil Removal BC-1 CS-8 CS-12 CO 2 alone -3 1 0 CO 2 + Hydrogen peroxide 26 13 33 CO 2 + Caroat 61 52 61

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• 2000
  • 2000-12-05 EP EP00204345A patent/EP1111032A1/de not_active Withdrawn

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