US 2697075 A
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United 2,697,075 Patented Dec. 14, 1954- free DRY-CLEANING coMPosrrroNs Robert E. Echols, El Cerrito, Calif, assignor to California Research Corporation, San Francisco, Caiifi, a corporation of Delaware No Drawing. Application December 21, 1951,
erial No. 262,910
4 Claims. (Cl. 252170) The present invention relates to an improvement in dry-cleaning compositions. 7 One of the most widely employed dry-cleaning solvents for cleaning soiled fabrics and clothes is the white spirits fraction of petroleum known in the art under the name of Stoddard solvent or cleaners naphtha. This solvent is a petroleum distillate characterized by a flash point of not lower than 100 F. (Tag. closed cup test) and distilling over to not less than 50% at 350 F. with the end point being not higher than 410 F. It has a density of about 6.5 pounds per gallon and is furthermore characterized by negative doctor, copper-strip corrosion, and non-volatile acidity tests.
It is a common practice in the dry-cleaning industry to add to the Stoddard solvent present in the wash wheel various surface-active agents such as potassium, ammonium or amine soaps of fatty acids as cleaning aids in order to enhance the cleaning action of the Stoddard solvent. These surface-active dry-cleaning soaps, in addition to being eitective as detergents, should possess no obnoxious, persistent odors, and finally must have good dispersing properties to secure satisfactory whiteness retention by preventing redeposition of the soil on the fabrics.
An efiiciently operated dry-cleaning plant is one where the bulk of cleaning is done by agitation in the wash wheel and the costly, time-consuming spotting is reduced to the minimum. For this reason, the operator often desires to add water to the Stoddard solvent in the wash wheel so that not only the oil-soluble stains but also the watersoluble stains could be removed there. Hence, it is desirable that the surface-active additives to dry-cleaning solvents act not only as detergents and dispersants for the soil, but also be capable of emulsifying water in the Stoddard solvent in such amounts as to remove effectively most, if not all, of the water-soluble stains during the wash wheel treatment, thus cutting down the spotting work and, if possible, dispensing with the wet-cleaning step (water-wash) of fabrics or garments.
The present invention provides a dry-cleaning detergent or wet soap which is capable of removing oilsoluble stains, even though in the presence of watersoluble soil, and prevents redeposition of the soil during the treatment in the wash wheel, thereby securing satisfactory whiteness retention and at the same time effecting the emulsification of substantial amounts of water in the dry-cleaning (Stoddard) solvent to enable an effective removal of water-soluble stains.
In accordance with the invention, effective dry-cleaning detergent, water-emulsifying compositions are prepared by dissolving in the Stoddard solvent a surfaceactive nonionic polyoxyalkylene ether of a mono-alkyl phenol, the alkyl group of the phenol portion in the molecule'of this other containing an average of l4carbon atoms, while the polyoxyalkylene portion of the same ether molecule contains from 5 to 7 ethylene oxide units, said ether being present in solution in the Stoddard solvent in amounts ranging from about 10 to about 30% by weight, and
preferably from about to about by weight, based on the weight of the solvent.
The ethers suitable for use in the preparation of drycleaning compositions of my invention may be produced in any suitable manner, a preferred method consisting in heating a Chi-alkyl phenol, adding thereto a catalytic amount of a caustic alkali or other suitable base, and contacting this mixture with ethylene oxide at a temperature which generally ranges from about 150 to about 200 C. The length of the polyalkylene chain in the resulting ethers is determined by the proportion of ethyl: ene oxide caused to react with the alkyl phenol. The ethylene oxide may be added either in the gaseous or in the liquid phase. The technique of such a preparation is dedescribed, for instance, in U. S. Patent No. 2,213,477 to Steindorfi et al., although other suitable techniques resulting in the formation of a polyoxyalkylene ether of Cit-alkyl phenol containing from 5 to 7 ethylene oxide 'mits in the oxyalkylene portion thereof may also be :mployed.
The addition of such an ether dissolved in the Stoddard solvent to the bulk of the solvent in the wash wheel not only enhances the cleaning action of the solvent, but, owing to the dual lipophilic-hydrophilic nature of this ether, enables the emulsification of water in the Stoddard solvent with water being finely and uniformly dispersed throughout the solvent. These emulsions are stable and do not undergo phase separation, irrespective of the fact whether the water employed for emulsification is hard (300 ppm.) or soft ppm.). In addition, because of the absence of free fatty acids, there is no build-up of rancid fatty odors in garments cleaned in the solvent containing the polyoxyalkylene ethers of my invention.
An effective stock emulsion capable of remaining stable for at least a full day and displaying no separation of phases for at least 8 hours can be readily prepared by mixing, or homogenizing, one part by volume of a 10 to 30% solution of the aforedescribed non-ionic polyoxyalkylene ether of C14-alkyl phenol in the Stoddard solvent with 1 part by volume of water and 1 part by volume of fresh Stoddard solvent. This stock emulsion may be added to the dry-cleaning solvent in the wash wheel, whenever its addition appears desirable in the course of the wash Wheel treatment of garments, at the rate of /2 to 1% ounces per pound dry weight of garments to be cleaned, regardless of the fabric involved, dispersing uniformly in the dry-cleaning solvent. The necessity of having 5 to 7 ethylene oxide units in the polyoxyalkylene portion of the ether of Chi-alkyl phenol is a critical limitation because emulsions made with the polyoxyalkylene ethers containing less than 5 mols of ethylene oxide are not sufliciently stable, while emulsions made with ethers containing more than 7 mols of ethylene oxide revert to oil-in-water type emulsions and do not disperse in the Stoddard solvent when added to the wash wheel content.
In a typical dry-cleaning plant with a wash wheel containing about 150 pounds of Stoddard solvent and capable of treating loads of from 150 to 200 pounds dry weight of soiled fabrics and garments, the addition to the solvent in the wash wheel of a water-in-oil type emulsion of my invention containing from 30 to parts by weight of Stoddard solvent and from 35 to 55 parts by weight of water, the remainder to make up parts by weight being the aforementioned polyoxyalkylene ether of Cir-alkyl phenol, markedly enhances the eifectiveness of the wash wheel treatment and the removal of oil-soluble and watersoluble soils, and greatly improves the pass-up rate, as will be shown by the data hereinafter.
The effective polyoxyalkylene ethers of C14-alkyl phenol may also be added to the solvent in the washwheel either as 100% active materials or as a solution in Stoddard solvent, but in any event in such proportions as to permit emulsification of water in an amount equal to from r about 0.25 to about 1.0%, and sometimes more, based on the total weight of the solvent in the wheel. These proportions correspond to from about 0.03 to about 0.12% of polyoxyalkylene ether, based on the total weight of the solvent. In these cases, the water is generally added to the solvent in the wheel either in the form of steam or as a fog through a spray nozzle, thereby assisting in a more uniform dispersion.
It was found that among the various polyoxyalkylene ethers of C14-monoalkyl phenol containing from 5 to 7 ethylene oxide units in the polyoxyalkylene portion thereof, those ethers in which the number of ethylene oxide units averages 5.5 are particularly effective when employed for cleaning woolen fabrics and garments. As a matter of fact, the number of pass-ups, i. e., garments cleaned in the wash wheel and requiring no additional spotting treatment (manual removal of soil spots after the wash wheel cycle), is found to be increased by as much as to as a consequence of the introduction. into the Stoddard solvent contained in the wash wheel of a stock emulsion made up of one part by volume of Water in one part by volume of Stoddard solvent and one part of a 10 to solutionofthe aforementioned ether in the Stoddard solvent.
An example of the many procedures which may be employed in cleaning garments with. the aid of the stock emulsion of this invention is as follows: A load consisting from about 150 to 200 pounds of garments to be cleaned is placed into the wash wheel containing. about 175 gallons of Stoddard solvent. The wheel is started up, and the stock emulsion of water in the Stoddard solvent emulsified with the aid of the aforedescribed polyoxyalkylene ether of Cii-alkyl phenol is added to the contents of the oscillating wheel, the preferred. proportions being about 1 liquid ounce of. the emulsion per 1 pound dry weight of the garments, which proportion corresponds to a concentration of from about 0.29 to about 0.40% by weight of water, and about 0.05 to about 0.07% by weight of the non-ionic ether, based on the weight of the Stoddard solvent in the wash wheel. After oscillating the wheel for about 12 to 15 minutes, a filter aid, e. g., diatomaceous earth, is added to the. Stoddard solvent in the Wash wheel, whereupon the solvent is recycled through a pressure filter for. about 20 minutes, a time theoretically necessary to give about 12 changes ofthe solvent. This recycling treatment removes, the filter aid from the filter. together with. particles of the soil, part of the non-ionic ether, and a portion of the. moisture. The cleaned clothes are then placed in a. laundry type centrifuge to extract most of the solvent, and finally are subjected to-drying in a heated tumbler. After drying, the garments are inspected, and the remaining spots are removed with a steam brush or a suitable spotting solution. If necessary, the garments may be re-run through the cleaning cycle or may be wet washed. ln addiswatch of wool cloth and of rayon cloth, both soiled with the. samestandardsoiL mixture. consisting of. lampblack, a commercial petroleum automobile lubricating oil, and a vegetable fat commonly known under the trade-name of Crisco. These three ingredients were thoroughly milled together on a roller-type paint mill, and were diluted with carbon tetrachloride. The cloth was passed through this-dilution.. A small. quantity of acetone was added when soiling the rayon clothto effect better adhesion. Average. soil removal values for atypical cleaning plant were" found. to rangebetween about 7.0 to. 75 for woolens and 80% for rayons. The. greying:v ordinarily did not exceed 5%, and the shrinkage 2%.
In an=extendedttest ll1LWhlCh-t large batch of 400 pounds of the non-ionic ether' of. Cm-alkyl phenol containing an average of 5.5 ethylene oxide units was employed in an emulsion in Stoddard solvent on Woolen garments, the pass-up rate was found to range from to 90%, corresponding to an average rate of 75%. for woolen garments as compared with the normal rate for woolens of about 50%. Two loads of. predominantly gabardine garments (which are usually very difiicult to clean as corn-v pared to the softer woolens) had a pass-up rate ranging from 69 to 75%.v Again, in another series of runs, where stock. emulsions made from. 20, 25 and 28.5% solutions of a polyoxyalkylene ether (5.5 ethylene oxide units.) of Cm-alkyl phenol. were employed on. woolen garments, the average. pass-up rate obtained; was 67%.
The following table illustrates the advantages gained by a. dry-cleaning; establishment. through the employment of stock emulsions formulated in accordance with the aid of non-ionic.polyoxyalkylene ether of Cm-alkyl phenol.
For the sake of comparison, this table also contains the results of tests in which a conventional surface-actiye dry-cleaning aid. consisting of a reaction product of ethylene oxide and oleic acid has been employed to improve. the. washwheel treatment of soiled woolen garments.
Soil removal vnlues'and pass-up rate T e Wool Soil Rayon Soil Pass'Up Spotting Washing Added Detergent g Removal, Removal, Greying Shrinkage Rate, Required, Required,
Percent Percent Percent: Percent Percent C -monoalkyl phenol ether contain- Dark woolus-.- o2 86 2'. 7 r 0.5 6415 34.2 1.3
ing 5' ethylene oxide units (20% solution).
Similar ether containing 5.5 ethylene Mixed woolens- 99 98' 2; 5 1. 3 I 66. 7 29. 0 4. 3
oxide units (20% solution).
Similar ether containing 5 ethylene do i 84 86 3.5 1.0. 63.0 2&8. 7.2
oxide units (20% solution).
Reaction product of ethylene oxide d0 1. 5' 57: 3 37. 9 4.8
and oleic acid (20% solution).
Ou-monoalkyl phenol ether containdo 81.51 2. 5. 75.0 20. 0 5. 0
ing 5.5 ethylene oxide units (20% solution).
Reaction product of ethylene oxide 1 0 1.3 57.0 36'. 0. 7.0
and oleic acid (20% solution).
C'll-monoalkyl phenol ether contain- 92 87 1. ti; 0 9 67.0 28. 0 5. 0
ing 5.5 ethylene oxide units (20% Sol tion).
Cn-monoalkyl phenol ether containdol 91 88. 5-
ing 5.5 ethylene oxide units (25% solution).
Similar ether, but in a 28.5% solution do v2 89' 1. 8 0.9 v 64. 5 30.0 5 5 Reaction product of ethylene oxide do 88 85 5.0 2.0- 60.6 36. 6 2-3 and oleic acid (20% solution).
rr OHOH-IkYl phenol ether containdo 93 91 60.0
mg 6.5 ethylene oride units.
tion. to recording the increase. in the number' of passups made possible. through the employment of the stock emuls on of my invention containing. the non-ionic polyoxyalkylene ether of Cwalkyl phenol, I madea number of determinations of the so-called soil removal? values in per cent in each run for the purpose of evaluating the etfectiveness of my new dry-cleaning composition. These soil removal values are found in accordance with. a speclally evolved testing technique; A test. bundle of five swatches of cloth was pinned to a garment to be cleaned, and after the garment had gone through a complete cleaning. cycle the test bundle was subjected to reflectance measurements in a conventional type of reflectometer, such as Hunter lrellectometer. Each test bundle consisted of the five following swatches. of cloth: One swatch of rayon spotted with berry juice, coffee, egg and soup; one clean swatch of rayon for determining the extent of S011 re-deposition (greying); onev swatchv of wool with a square of known dimensions printed in ink. thereon for the purpose of measuring. shrinkage; and finallyone An important advantage attendant. to the employment of the aforedescribed effective non-ionic polyoxyalltylene ether of'Cm-alkyl phenol, or of the aqueous stock emulsion formulated therewith, resides in the fact that their application in no way interferes with the reclaiming (clean-up) of the Stoddard solvent, provided conventional distillation techniquesare employed. The Stoddard solvent being lower boiling distills overhead first, and the non-ionic ether is withdrawn together with the soil and other bottoms materials.
Finally, it should be understood that the specific limitations in the above description as given by way of examples in the table hereinabove are not intended to restrict.in any way the scope of the invention as defined in the annexedclaims.
1. A dry-cleaning composition which. comprises a solution in Stoddard solvent of a polyoxyalkylene ether of an alkyl' phenol, the alkyl group of the phenol portion in the ether molecule containing an average of 14 carbon atoms and the polyoxyalkylene portion in said ether molecule containing from 5 to 7 ethylene oxide units, said ether being present in an amount equal to from about 10 to about 30% by weight of the total amount of Stoddard solvent, and being capable of emulsifying Water in the Stoddard solvent in a proportion up to an equivalent amount thereof.
2. A dry-cleaning composition as defined in claim 1, in which said ether is present in an amount equal to from about to about by weight of the total amount of Stoddard solvent.
3. An effective, stable dry-cleaning water-in-oil type emulsion containing from to 60 parts by Weight of Stoddard solvent, from to parts by Weight of water, the remainder to make up 100 parts being a polyoXyalkylene ether of an alkyl phenol, the alkyl group of the phenol portion in the ether molecule containing an average of 14 carbon atoms and the polyoxyalkylene group in said ether molecule containing from 5 to 7 ethylene oxide units, said emulsion being capable of dispersing uniformly in Stoddard solvent Without phase separation.
4. An effective, stable dry-cleaning water-in-oil type emulsion containing from 30 to parts by weight of Stoddard solvent, from 35 to 55 parts by weight of water, the remainder to make up parts being a polyoxyal- &
kylene ether of C14-alky1 phenol, the polyoxyalkylene group in said ether containing an average of 5.5 ethylene oxide units, said emulsion being capable of dispersing uniformly in Stoddard solvent without phase separation.
References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Surface Active AgentsPerry and Schwartz Interscience Pub., Inc., N. Y. 1949, page 204.
The Chemical FormularyBennett Chemical Pub. Co., N. Y. Vol. VIII 1948, page 348.
The Chemical Formulary-Ben11ett Chemical Pub. Co., N. Y. Vol. IX 1951, pp. 535, 536.