US 2056141 A
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Patented Sept. 29, 1936 UNITED STATES V 2,056,141 PATENT OFFICE METHOD OF CLEANING FABRICS Latimer D. Myers, Cincinnati, Ohio, assignor to Emery Industries, Inc., Cincinnati, Ohio, a cor poration of Ohio No Drawing. Application May 11,1933, Serial No. 670,536
such as gasoline, naphtha, benzine, or chlorinated hydrocarbons, such as carbon tetrachloride, trichlorethylene. The term fabrics is used herein to comprehend garments, draperies, rugs, and other articles of the type now being cleaned in the existing commercial dry cleaning establishments.
The dry cleaning process is primarily one of removing oils and greases which are readily solvent soluble. The removal oflthe oils and greases also effects a removal of particles of soil for which the oils and greases act as binding agents. The,
tumbling and abrasion received in the washer assists in this removal.
Although particularly effective in removing oils and greases, the solvent cleaning method, due to the very nature of the process, is not well-adapted to the removal of water soluble soil, soil which.
is bound to the fiber by-water soluble material, or
spots caused by water having come in contact with and roughened the material used in sizing the fabric.
At the present time the water soluble soil and the so-called water spots are usually removed by hand spotting with water or an aqueous soap solution- This hand spotting and alternative .methods are expensive, damage the garment in many cases, and often merely enlarge the soiled area.
The object of this invention is to provide a dry cleaning-process in which the water soluble soil and the water'spots are removed as a part of the dry cleaning operation and simultaneously therewith. It is also the object of this invention to provide a fabric cleaning process in which the fabrics are not only dry cleaned, but in which the. appearance of the fabrics, particularly the brightness of the colors and the texture of the finish, are materially improved.
The invention comprises adding moisture to the fabrics-by subjecting them to a predetermined and controlled humidiflcation preceding the conventional dry cleaning. Inasmuch as different textile fibers are sensitive to moisture to different degrees, and likewise absorb moisture to different extents, and at different rates, it may be found desirable for obtaining the very best results on specific types of fabric to perform a fabric sorting step antecedent to the humidiiication in order to segregate the fabrics into batches of relatively uniform moisture absorbing properties.
Generally speaking, the humidifloation step of this process is exemplified by subjecting the fabrics at a temperature of approximately 75 F. to an atmosphere having a relative humidity of 60% to 90% for a period of between 20 and 40 minutes. The production and maintenance of an atmosphere of any desired or given humidity is well within the skill of the air-conditioning art so no disclosure is made herein in regard to methods or apparatus for creating, maintaining and controlling the relative humidity. It is, of course, desirable that a. batch of fabrics of known moisture sensitivity be segregated in an atmosphere of predetermined relative humidity and that the.
relative humidity be maintained or controlled within the established limits for a predetermined length of time.
It will, of course, beunderstood by those skilled in the art that the actual quantity of moisture in the atmosphere varies with the relative humidity and that the relative humidity varies with the temperature. Therefore, the selected temperature of 75 F., while highly practical and recommended, is not critical, and any temperature may be chosen for carrying out the humidification'provided the length of treatment and the relative humidity employed does not cause an absorption of moisture by the fabric greater than the moisture tolerance of the fabric. In this particular case the term moisture tolerance of the fabric is used to indicate not only that point at which the fabric is saturated with moisture, but the point at which the fabric is adversely affected by moisture as might be evidenced by shrinkage, bleeding of color, roughening of the sizing, and damage added should be calculated in respect to the moisture content of the fabrics which is optimum when the ensuing dry cleaning operation is performed. The moisture contents generally desirable for different fabrics are as follows:
Per cent Cotton 8 to 13 Silk to 15 Wo l 10 to Cellulose nitrate rayon 12 to 20 Cuprammonia rayon 12 to 20 Cellulose acetate rayon 5 to 10 Viscose rayon 12 to 20 While it may seem to be a rather complicated matter to incorporate the optimum amount of moisture in each one of the diiferent specific fibers, still, as a practical matter, the accomplishment is more simple than it seems. This is due to the circumstance that the textile fibers now most commonly used happen to be moisture sensitive somewhat in proportion to their.
tendency to absorb moisture. In other words; the textile fibers which absorb moisture more slowly have in general lower moisture tolerance so that it is not diflicult to select humidiflcation conditions which elevate the moisture contents of 'a variety of fibers into the generally desirable range for each. Of course, this involves a certain amount of compromise and provides results which may be thought somewhat inferior to the theoretically best results. However, as a matter of practical dry cleaning, the results with the compromise humidification conditions are not only sufllciently satisfactory, but are far superior to those provided by the usual dry cleaning treatment.
After the step of adding moisture to the fabrics to bring the total moisture content into the desired range, the fabrics are subjected to routine dry cleaning treatment with the added moisture still present. It is, however, recommended that an agent-be used for reducing the interfacial tension between the cleaning solvent and the textile fibers containing the moisture. A number of the so-called filter dry cleaning soaps on the market are suitable for this purpose.
The following three formulae provide interfacial tension depressants suitable for this use when used in the dry cleaning solvent in the proportion of 4 to 6 gallons to 100 gallonsof solvent.
Per cent 1. Oleic a 7 30 Solvent (naphtha) 45 Monobutyl ether of ethylene glycol; 15 Potassium hydroxide 5 Water -5- Per cent 2. Oleic a 1 53.0 Ethylene glycol monoethyl ether 13.2 Potassium hydroxide 4.2 Trietha c I 10.6 Water 5.8 Solvent (naphtha) 13.2
- Parts 3..Oleic acid 48.8 Potassium hydroxide 5.6 NH4OH 26 36 .3 Water 6.4 Alcohol 5.0
, Solvent 34.0
It is believed that the cleaning, brightening and rejuvenating accomplished by this process is a result of abrasive action received by the fabric due to the tumbling action in the washer, the water spots and water soluble soil having been loosened by the humidification. Moreover, when an'interfaoial tension depressant of the nature disclosed is used in practicing this process, there is a tendency for the moisture in the fabric to transfer to the cleaning solution and back again to the fabric so that one might sayv that there is a; constant and mutual interchange of moisture between the solution and the fabric. This interchange likewise assists in the removal of water soluble soil and in brightening the finish of fabrics which have been finished with a water sensitive size.
Altogether, this cleaning treatment removes greasy soil, water soluble soil, water spots, per-- spiration marks, unless the fabric or dyestuff has been injured thereby, and in general, betters the tone and appearance of the fabrics so that the process may be said to rejuvenate the fabrics.
Having described the invention, I desire to be limited only by the following claims:
1. The method of cleaning fabrics, which com prises, adding moisture to the fabrics, the amount not exceeding the moisture tolerance of the fabrics, by subjecting the fabrics to humidification as exemplified by exposure to an atmosphere of 60 to 90% relative humidity for between 20 and 40 minutes at a temperature of F., and then cleaning the fabricswith the added moisture still present, in a dry cleaning solvent.
2. The method of cleaning fabrics which comprises adding moisture to the fabrics, the amount not exceeding the moisture tolerance of the fabrics, by subjecting the fabrics to humidification as exemplified by an exposure to an atmosphere of 60 to percent relative humidity for between 20 to 40 minutes at a temperature of 75 F.,- and then cleaning the fabrics, with the added moisture still present, inv a drycleaning solvent'containing a filter dry cleaning soap.
, LATIMER D. MYERS.