However, in recent times a desire has arisen in the marketplace to discontinue using these dry cleaning solvents. Health and environmental concerns have rendered perchloroethylene undesirable as a dry cleaning solvent, whereas the ever present fire hazards and the occurrence of skin sensitivity problems have made it undesirable to continue using hydrocarbon solvents as dry cleaning agents Other chlorinated or chlorofluorinated solvents have become unavailable or undesirable because of governmental regulations, high cost, or for reasons relating to performance Thus it has become of commercial importance to see if a successful replacement solvent composition can be discovered that avoids the problems associated with previously-used dry cleaning solvents, especially perchloroethylene and hydrocarbon dry cleaning solvents To find a new dry cleaning solvent composition for fabrics is a difficult task.

Besides avoiding health and environmental concerns, and fire hazards, the composition must be effective in cleaning a wide variety of fabrics without causing damage to the fabrics being cleaned. Also the composition must be capable of being used in various types of presently-used dry cleaning machines without requiring substantial changes or modifications in the machines or their operation, and without damaging the metal parts of the machines. This invention is believed to fulfill all of these requirements very effectively.

SUMMARY OF THE INVENTION Surprisingly this invention makes it possible, not only to satisfy all of the above

requirements, but also to provide dry cleaning compositions for fabrics that can provide excellent cleaning, less fabric wrinkle, less heat shrinkage, reduced ironing requirements, and soft fabric finish using short cleaning cycle times. These advantages can be achieved in accordance with this invention by providing and using a liquid dry cleaning solvent composition for fabrics, such composition comprising (i) at least one 1-bromoalkane having 3 to 6 carbon atoms in the molecule, (ii) a fabric-softening amount of at least one surfactant, such as an anionic or nonionic surfactant, and (iii) a stabilizing amount of a stabilizer for the composition.

Another embodiment of this invention is a method of cleaning fabrics which comprises washing the fabrics in a dry cleaning machine in which the dry cleaning solvent is a liquid dry cleaning solvent composition of this invention.

A method of removing oleaginous spots or stains from fabric, which method comprises applying at least to the spotted or stained area on the fabric a liquid dry cleaning solvent composition of this invention is another embodiment of this invention Other embodiments and feature of the invention will be still further apparent from the ensuing description, accompanying drawing, and appended claims.

BRIEF DESCRIPTION OF THE DRAWING Fig. 1 is a schematic flow diagram of typical industrial dry cleaning machines in which the compositions of this invention can be used for cleaning various dry-cleanable fabrics.

FURTHER DETAILED DESCRIPTION OF THE INVENTION Solvent Component More than 50 percent by weight, and preferably more than 90 percent by weight, of the compositions of this invention is composed one of more liquid 1-bromoalkanes having in the range of 3 to 6 carbon atoms in the molecule Such 1-bromoalkanes are preferably linear 1-bromoalkanes, although some (e-g., 5 wt% or less and preferably 2 wr% or less) of the 1-bromoalkane component can be one or more branched chain 1- bromoalkane isomers in which the bromine atom is attached to a primary carbon atom.

It is preferred that the solvent portion of the composition be composed entirely of one or more 1-bromoalkanes having 3 to 6 carbon atoms in the molecule (including up to

5 wt% of impurities normally present in industrial grades of such 1-bromoalkanes, and preferably no more than 2 wt% of such impurities). However it is possible to use blends of one or more of the 1-bromoalkanes with up to 40 percent by weight of the solvent components (excluding the weight of additives) being perchloroethylene and/or a hydrocarbon dry cleaning solvent such as petroleum solvents composed of paraffin, naphthene and/or aromatic hydrocarbons that have boiling points in the range of about 120 to 220 °C, or mineral spirits that boil in the range of 150 to 210°C If such blends are used, it is preferred to minimize the percentage of the perchloroethylene and/or hydrocarbon dry cleaning solvent as much as possible. In other words, the lower the amount of the solvent component (i. e., perchloroethylene and/or hydrocarbon solvent), the better, with the total absence of such perchlorethylene and hydrocarbon solvent being most desirable.

The most preferred 1-bromoalkane from the cost-effectiveness standpoint for use in the practice of this invention is 1-propylbromide (also known as n-propylbromide or 1- bromopropane) having a purity, when devoid of additives, of at least 98 wt%.

Surfactant Component A fabric-softening amount of at least one surfactant is employed in the compositions of this invention. This amount will vary somewhat depending upon the composition of the surfactant and the makeup of the particular solvent being used pursuant to this invention. Typically however, the compositions of this invention will contain in the range of 0.05 to about 2 percent by weight, and preferably in the range of 0.1 to 1 percent by weight, of one or more such surfactants based the total weight of the composition Preferred surfactants are anionic or nonionic surfactants, although cationic surfaciants can also be used. The surfactants used in the practice of this invention are soluble in the solvent, and are compatible with the stabilizer system employed.

Among suitable anionic surfactants are alkanolamine salts of alkyl sulfates, alkanolamine salts of polyoxyalkylene alkyl sulfates, and alkanolamine salts of alkylaryl sulfonates. The alkanolamine counter ion of such salts can be derived from various alkanol amines which typically have boiling points above 200°C, such as for example diethanolamine, triethanolamine, dibutylethanolamine, and methyldiethanolamine. The

alkanolamine salts of alkyl sulfates, and the alkanolamine salts of polyoxyalkylene alkyl sulfates can be depicted by the formula: where R is a hydrogen atom or a methyl group, R'is an alkyl group having 10 to 20 carbon atoms, n is an integer from 0 to 6, and Z is the alkanolamine counter ion. A few examples of such sulfates include dibutylethanolamine dodecyl sulfate, methyldie- thanolamine polyoxyethylene (2) dodecylsulfate, and diethanolamine polyoxyethylene (6) dodecyl sulfate.

The alkylaryl sulfonate alkanolamine salts can be depicted by the formula : R2ArSO3Z where R2 is an alkyl group of from 8 to 20 carbon atoms, Ar is a phenyl or naphthyl group, and Z is an alkanolamine counter ion. Diethanolamine dodecylbenzene sulfonate is a typical example of such surfactants Preferred surfactants of this type are those in which RI is an alkyl group of from 10 to 16 carbon atoms, Ar is a phenyl group, and Z is a counter ion derived from a dialkylalkanolamine in which each of the two alkyl groups is, independently, a linear or branched alkyl group having 2 to 4 carbon atoms, and the alkanol moiety of the compound has 2 or 3 carbon atoms, and especially where the alkanol moiety is an ethanol or isopropanol moiety.

Other anionic surfactants that can be used include petroleum sulfonates and dialkylsulfosuccinic acid salts in which each alkyl group has in the range of 6 to J 0 carbon atoms, such as sodium di (2-ethylhexyl) sulfosuccinate, sodium di (n-octyl) sulfosuccinate, and sodium di (decyl) sulfosuccinate.

Nonionic surfactants that can be used include, for example, polyoxyethylene nonylphenylethers having 2 to 20 moles of added ethylene oxide units, polyoxyethylene alkyl ethers having 2 to 20 moles of added ethylene oxide units and in the range of 10 to

20 carbon atoms in the alkyl group, fatty acid sorbitan esters and fatty acid alkanolamides derived from fatty acids having in the range of 10 to 20 carbon atoms and monoethanolamine, diethanolamine, monoisopropanolamine, or diisopropanolamine, or a mixture of any two or more of these alkanolamines.

Cationic surfactants which can be used include quaternary ammonium salts which preferably have one or two long chain alkyl or alkenyl groups each having in the range of 12 to 22 carbon atoms, and three or two Cl 3 alkyl or C, 3 hydroxylalkyl groups in which the hydroxy group is in a terminal position-A few non limiting examples of these quaternary ammonium salts include dilaurylmethylhydroxyethyl ammonium chloride, dicetylethyl-2- (hydroxyethoxy) ethyl ammonium bromide, distearylmethylhydroxyethyl ammonium chloride, di-2-hydroxydocosylethyl-2- [hydroxy (diethoxy)] ethyl ammonium ethyl sulfate, dilauryldihydroxyethyl ammonium acetate, dimyristylhydroxyerhyl-2- (hydroxyethoxy) ethyl ammonium propionate, dihydrogenated beef tallow alkyl- methylhydroxyethyl ammonium chloride, di-hydrogenaied beef tallow alkyldihydroxyethyl ammonium bromide, dipalmiryl-di-2-hydroxypropyl ammonium 2-hydroxyacetate, and mixtures of two or more of such quaternary ammonium salts.

Mixtures of one or more anionic surfactants with one or more nonionic surfactants, mixtures of one or more anionic surfactants with one or more cationic surfactants, mixtures of one or more nonionic surfactants with one or more cationic surfactants, and mixtures of one or more anionic surfactants with one or more nonionic surfactants and one or more cationic surfactants can be used in the compositions of this invention, provided of course that the mixture used is not only effective in assisting in removing and inhibiting redeposition of solvent-soluble soils such as, for example, various fats, oils, waxes, hydrocarbons, and fatty acids, including human sebum and decomposition products of sebum, but does not cause appreciable damage to the fibers of the fabric being cleaned or bleading of dyes in the fabric being cleaned. Thus in general, any suitable surfactant or suitable combination of surfaciants can be used in the compositions of this Invention The selected surfactant or surfactants can be added to the composition either ar the site of the producer of the composition or the selected surfactant or surfactants can be added at the site of the dry cleaning establishment. It is also possible to add one or more surfactants at the production site and thereafter have one or more same or different surfactants added at the site of the dry cleaning establishment. In this case it is important

that the surfactants used at the respective locations be compatible with each other, and that the quality of the performance not be spoiled by the addition of one or more surfactants by the operator of the dry cleaning establishment.

Besides cleaning the fabric, the surfactants used contribute to the softening, i. e., the good feel, of the washed and dried fabric, especially when the solvent of the composition of this invention used in the washing step is n-propyl bromide.

Stabilizer Component The compositions of this invention contain a stabilizing amount of one or more stabilizer components. Suitable types of stabilizer components include, for example, mononitrohydrocarbons, epoxides, 1,3-dioxolanes, aliphatic ethers, and amines The mononitrohydrocarbons include such compounds as nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, nitrocyclopentane, 1-nitro-1-cyclohexene, nitrobenzene, 2-nitro-p-cymene, and mixtures of two or more such compounds.

Among suitable epoxides are such compounds as propylene oxide, 1, 2-butylene oxide, 2,3-butylene oxide, cyclopentene oxide, cyclohexene oxide, glycidyl methyl ether, glycidyl methacrylate, epichlorohydrin, and mixtures of two or more such compounds.

The 1,3-dioxolanes are typified by such compounds as 1,3-dioxolane, 2-methyl- 1,3-dioxolane, and 4-methyl-1, 3-dioxolane. These compounds can be used singly or in mixtures of two or more of them.

Suitable aliphatic ethers include such compounds as diethyl ether, dipropyl ether, diisopropyl ether, methyl tert-butyl ether, methyl ter-amyl ether, methyl propargyl ether, dibutyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylglycol dimethyl ether, triethylglycol dimethyl ether, tetraethylglycol dimethyl ether, and mixtures or two or more such compounds.

Among suitable amines are included such compounds as diethanolamine, triethanolamine, diisopropylamine, butylamine, peniylamine, hexylamine, octylamine, decylamine, cyclohexylamine, aniline, p-ethylaniline, benzylamine, diethylamine, dibutylamine, diheprylamine, diallylamine, dicyclohexylarnine, N-methylaniline, dibenzylamine, triethylamine, tributylamine, trioctylamine, N, N-dimethylaniline, ethylenediamine, p-phenylenediamine, and mixtures of two or more such compounds.

Other suitable stabilizer components include such compounds as phenols, such as phenol, cresols, ethylphenols, and xylenols; acetylenic alcohols such as 2-butyn-1-ol, 3- butyn-1-ol, 2-pentyn-1-ol, 3-pentyn-1-ol, 4-pentyn-1-ol, and 4-pentyn-2-ol; triazoles such as benzorriazole ; and heterocyclics such as N-methylmorpholine.

In the compositions of this invention the stabilizer or mixture of stabilizers is typically present in an amount of up to about 10 wt% of the total weight of the composition.

Mixtures of stabilizers taken from two or more of the above types are preferred.

One preferred mixed stabilizer used in the practice of this invention is a combination of (i) at least one nitroalkane, most preferably nitromethane, and (ii) at least one epoxide, most preferably 1, 2-butylene oxide. Such stabilizer combination is typically used in an amount such that the composition contains from 0.2 to 1 wt% of (i) and from 0.2 to 1 wt% of (ii), with the wt% of each most preferably being approximately equal to each other (e. g., not differing by more than 0.2 wt% from each other) Particularly preferred is a composition comprised of 1-bromopropane of a purity of at least 98 % as the solvent, and in which the stabilizer system comprises 0.4-0.6 wt% of nitromethane and 0.4-0.6 wt% of 1, 2-butylene oxide-Another preferred mixed stabilizer used in the practice of this invention is a combination of (a) at least one nitroalkane, most preferably nitromethane, (b) at least one epoxide, most preferably 1, 2-butylene oxide, and (c) at least one aliphatic polyether and/or at least one 1,3-dioxolane or alkyl-substituted 1,3- dioxolane, most preferably 1,3-dioxolane. Such stabilizer combination is typically used in an amount such that the composition contains from 0 2 ro 1 wt% of (a), from 0-2 to 1 wt% of (b), and from 1 ra 8 wt% of (c), with the wt% of (a) and (b) most preferably being approximately equal to each other (e. g., not differing by more than 0.2 wt% from each other), and with the wt% of (c) being at least twice, and more preferably at least three times, the total wt% of (a) plus (b). Particularly preferred is a composition comprised of 1-bromopropane of a purity of at least 98 % as the solvent, and in which the stabilizer system comprises 0. 4-0.6 wt% of nitromethane, 0.4-0.6 wu% of 1,2-butylene oxide, and 3. 6-6. 0 wt% of 1,3-dioxolane.

Other Components One or more components customarily used in dry cleaning operations can, in most

cases, be included in customary amounts in the compositions of this invention For example Cl 3 alkanols, 1101yhydric alcohol ethers (e. g., 2-methoxyethanol, 3- methoxypropanol, 4-methoxybutanol, and 2-ethoxyethanol), water, and antistatic agents, are among additional components that can be used in the compositions of this invention.

Articles for Cleaning This invention is applicable to cleaning typical articles made of fabric or textiles (which fabric or textile may include such things or accessories as buttons, zippers, other fasteners, and/or stuffing), that are normally subjected or subjectable to dry cleaning.

Some typical non-limiting examples of such articles are wearing apparel (e. g., suits, dresses, coats, jackets, sweaters, vests, trousers, slacks, skirts), and household articles (e. g., draperies, curtains, blankets, comforters, bed rolls, pillows, and tablecloths) made of fabrics. The fibers themselves can be natural fibers or synthetic fibers or blends of either or both.

Operating Equipment and Conditions One of the outstanding features of this invention is that the compositions of this invention can be used in many conventional dry cleaning machines without requiring significant change either in the machines and their auxiliaries or in the operating conditions of the machines. Moreover, the compositions of this invention can be used in both industrial cleaning machines (i e,, machines that are operated by member of the cleaning establishment) and in coin operated or self-serve machines where the person desiring the cleaning does the cleaning at an establishment. It is also possible to utilize the compositions of this invention in cleaning machines designed for operation in the home.

For example, compositions of this invention can be successfully used in machines designed specifically for use of perchloroethylene in industrial dry cleaning shops. In the case of machines of this type produced by one well-know commercial manufacturer in Japan, only a minor modification would be required. Indeed, indications are that the operation of machines in dry cleaning establishments could be readily switched from the presently-used perchloroethylene to a composition of this invention. It is anticipated that at most only some changes in the plastics used in such machines, such as the plastics used

in fabricating pipes, hoses, and gaskets, may prove desirable.

In addition, compositions of this invention can be used in machines designed specifically for use of 1,1,1-trichloroethane.

Tests in different machines of this type were found to give very satisfactory results with no machine modification required.

A schematic flow diagram of typical industrial dry cleaning machines is set forth in Fig. I In Fig 1, the term"soap"represents a surfactant system used pursuant to this invention. The steps involved in the operation include (a) tumbling the garments to be cleaned with a dry cleaning composition of this invention, (b) draining the solvent from the machine, and (c) centrifuging the wet garments. The liquids and vapors from the machines can be processed as indicated in Fig. 1. One type of machine performs the refrigeration in the chiller/refrigeraior at 10 degrees C with the harmless non-condensibles being released to the atmosphere In another type of machine the refrigeration is conducted at-30 degrees C, and the non-condensibles are passed into an air bag. If a garment to be cleaned has heavy greasy stains or spots, a composition of this invention can be applied either manually or by a spray directly onto to the stains or spots to serve as a spot remover before subjecting the garment to the dry cleaning operation-Such spot removing can be conducted after the dry cleaning, or both before and after dry cleaning, if desired. In high volume industrial dry cleaning establishments the garments may be hung on hangers and passed on a conveyor belt through saturated steam followed by drying using compressed hot air In smaller establishments, the garments after preliminary drying may be subjected to pressing.

Typically the washing step in the dry cleaning cycle will be conducted at temperatures in the range of about 25-30 degrees C, with the drying step typically being performed at about 55-60 degrees C. Of course it is possible to vary these temperatures as long as the fabrics being cleaned are effectively cleaned and are not harmed by using other temperatures. In tests conducted in a dry cleaning machine designed for use with 1, 1, 1-trichloroethane, very good results were obtained in a 29-minute cycle by washing in the solvent composition for 2 minutes, removing the solvent from the washer during a period of 4 minutes, drying the fabrics for 15 minutes, deodorizing for 6 minutes, and a fabric softening operation involving automatically rotating the tumbler drum for 2 minutes. The washing temperature was 20 degrees C. The drying was accomplished

using a drying temperature of 50 degrees C at the inlet and 40 degrees C at the outlet.

Vapor exposure was monitored by a detection apparatus placed one meter below the connection between the machine and the ventilator to the air. Only 10 ppm of vapors were detected under these conditions. Also it is known that the machine can be modernized to reduce vapor emissions even more.

In comparison with other dry cleaning compositions, the compositions of this invention offer a number of advantages. For example, evaluations have shown that the compositions of this invention rated number 1 out of a total of 7 dry cleaning compositions, 6 of which were based on other known organic solvents.

Other results indicate that fabrics cleaned with compositions of this invention give less wrinkle and less hear shrinkage. Also, the compositions of this invention make possible use of shorter cycle times, and less ironing, thus improving productivity in commercial establishments.

The following Examples illustrate, but do not limit, the scope of this invention EXAMPLE 1 A dry cleaning composition of this invention is formed by mixing together the following components: 98.5 wt% of n-propyl bromide (98% minimum purity; Albemarle Corporation) ; 0. 5 wt% dibutylethanolamine sulfate; 0.5 wt% nitromethane ; and 0.5 wt% 1, 2-butylen oxide.

EXAMPLE 2 Another dry cleaning composition of this invention is formed by mixing together the following components: 98.5 wt% of n-propyl bromide (98% minimum purity; Albemarle Corporation); 0.4 wt% diethanolamine polyoxyethylene (6) dodecylsulfate ; 0.1 wt % diethanolaminedodecylbenzene sulfonate ; 0.5 wt% nitromethane ; and 0.5 wt% 1,2-burylene oxide.

EXAMPLES Another dry cleaning composition of this invention is formed by mixing together the following components: 98.5 wt% of n-propyl bromide (98% minimum purity; Albemarle Corporation); 0.5 wt% diethanolaminedodecylbenzene sulfonate; 0.5 wt% nitromethane; and 0. 5 wt% 1,2-butylen oxide.

EXAMPLE 4 Another dry cleaning composition of this invention is formed by mixing together the following components: 98.5 wt % of n-propyl bromide (98% minimum purity : Albemarle Corporation) ; 0.5 wt% diethanolamide of oleic acid ; 0.5 wt% nitromethane ; and 0. 5 wt% 1,2-butylen oxide.

EXAMPLE S Another dry cleaning composition of this invention is formed by mixing together the following components: 98.5 wt% of n-propyl bromide (98% minimum purity; Albemarle Corporation); 0.3 wt% dibutylethanolamine dodecyl sulfate; 0. 2 wt% stearyltrimethylammonium bromide; 0. 5 wt% nitromethane; and 0. 5 wt% 1, 2-burylene oxide.

EXAMPLE 6 Another dry cleaning composition of this invention is formed by mixing together the following components: 94.5 wt% of n-propyl bromide (98% minimum purity; Albemarle Corporation) ; 0_5 wt% dibutylethanolamine sulfate; 4-0 wt% 1,3-dioxolane;

0. 5 wt % nitromethane ; and 0.5 wus 1,2-butylerxe oxide.

EXAMPLE 7 Another dry cleaning composition of this invention is formed by mixing together the following components: 94.5 wt% of n-propyl bromide (98% minimum purity; Albemarle Corporation) ; 0.4 wt% diethanolamine polyoxyethylene (6) dodecylsulfate; 0.1 wt% diethanolaminedodecylbenzene sulfonate ; 4. 0 svt% 1, 3-dioxolane ; 0. 5 wt% nitromethane ; and 0.5 wt% 1, 2-butylene oxide.

EXAMPLES Another dry cleaning composition of this invention is formed by mixing together the following components: 94. 5 wt% of n-propyl bromide (98% minimum purity ; Albemarle Corporation) ; 0. 5 wt% diethanolaminedodecylbenzene sulfonate ; 4.0 wt% 1,3-dioxolane; 0.5 wt% nitromethane ; and 0. 5 wt% 1,2-buylene oxide.

EXAMPLE 9 Another dry cleaning composition of this invention is formed by mixing together the following components: 94. 5 wt% of n-propyl bromide (98% minimum purity ; Albemarle Corporation); 0.5 wt% diethanolamide of oleic acid; 4. 0 wt% 1,3-dioxolane ; 0.5 wt% nitromethane ; and 0.5 wt% 1,2-butylene oxide.

EXAMPLE 10 Another dry cleaning composition of this invention is formed by mixing together the following components: 94.5 wt% of n-propyl bromide (98 % minimum purity ; Albemarle Corporation); 0.3 wt% dibutylethanolamine dodecyl sulfate ; 0-2 wt% palmityldimehylethylammonium ethyl sulfate ; 4.0 wt% 1, 3-dioxolane; 0.5 wt% nitromethane ; and 0_5 wt%a 1, 2-butylene oxide.

Other suitable compositions will now be readily apparent from the above description.