US2024981A

US2024981A - Absorbefacient for dry-cleaning

Info

Publication number: US2024981A
Application number: US637554A
Authority: US
Inventors: Warren T Reddish
Original assignee: Emery Oleochemicals LLC
Current assignee: Emery Oleochemicals LLC
Priority date: 1930-10-31
Filing date: 1932-10-12
Publication date: 1935-12-17
Anticipated expiration: 1952-12-17
Also published as: FR724081A; GB392931A

Description

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Patented Dec. 17, 1935 UNITED STATES- PATENT OFFICE Warren '1. Reddish, Cincinnati, Ohio, assignor to Emery Industries, Inc., Cincinnati, Ohio, a corporation of Ohio No Drawing. Continuation of application Serial No. 492,611, October 31, 1930. This application October 12,1932, Serial No, 637,554

3 Claims.

This invention relates to a new art of cleaning garments, fabrics, textiles, cloth, rugs, and articles of like nature, which for the sake of. convenience, throughout the remainder of the description will 5 be designated by the term fabrics unless otherwise specifically identified.

This application is a continuation of my application. Serial No. 492,611, filedOctober 31, 1930, and is a continuation in part in relation to my copending application Serial No. 590,981, filed Febt-uary .4, 1932, now issued into Patent No. 1,911,289, dated May 30, 1933. All the claims in the last identified application relate to a method of cleaning fabrics, whereas the claims in this application are directed to mahogany sulphonic bodies used as absorbefacients in the process described in that application, to the preferred absorbefacient itself and to the method of rendering a cleaning solvent moisture absorbent by the use of this specific type of absorbefacient.

to being practiced in so-called dry cleaning establishments, on the classes of articles usually cleaned there and with the types of equipment usually used there, the present invention is described and claimed as an improvement in the "dry cleaning art. However, the physical chemistry utilized in practicing this invention and the results obtained, are so contrary to the principles and go so far beyond results now designated by the term dry cleaning, that one might classify the fabric cleaning development of this invention as an entirely new art,

In order to comprehend the true novelty of prin- 'ciple of this invention, a brief review of the theories of previously known methods of cleaning fabrics is requisite. Cleaning fabrics has been accomplished in the past either by a soap and water process or by the dry cleaning process. The dry cleaning process differs in principle from the wet washing process.

In the wet washing process the dirt particles on the fabric are removed by emulsification and saponification of the oils and greases which bind the particles to the fabric. This is usually accomplished by washing the fabrics .with the ordinary fatty acid soaps which possess emulsifying powers in water solution and liberate alkali by hydrolysis which combines with the saponifiable oils present. These fatty acid soaps also lower the surface tension of the solution which accelerates the detergent action by increasing the rate of penetration of the soap and water into the fabric. The highly water soluble soil which may 55 also be present is removed, of course, by the $01- In view of. the fact thatthe invention lends itself vent action of the water. This process is in- J'urious to a majority of types of fabric because it often causes shrinkage, fading or disfiguration.

In the dry cleaning industry to which this invention is directed, a conventional cleaning sol- 6 vent is employed of the type exemplified by a volatile hydrocarbon or chlorinated hydrocarbon, the more commonly used of which are gasoline, naphtha, carbon tetrachloride and trichlorethylene. At present, the dry cleaning process is 10 usualy practicedby treating the fabrics in rotating drum type washers containing the cleaning solvent to which may be added suitable socalled dry cleaning soaps which decrease static' and lower surface tension. The agitation is continued for from ten to thirty minutes, depending upon the type of fabrics being treated and their condition. During this treatment, the oily or greasy film, which binds the dirt particles to the fabrics, is dissolved and the dirt particles are removed by the agitation of the fabrics in the solvent. The articlesare then rinsed in clean solvent and centrifugally extracted and then dried either in rotary drum type dryers or in heated rooms. By this treatment oily and greasy soil is removed without shrinkage of the fabric or damage to the sizing and finishing materials, the dyes or the fibre itself.

However, marks or disfigurations called water spots which are caused by water having come in contact with the fabric and roughened or partially dissolved the finishing material and spots caused by solely water soluble substances, such as perspiration, soft drinks, sugar syrups, and the like, are not removed by this process. It is, therefore, necessary to employ water or other suitable solvents to remove them. This is usually done by hand spotting of the affected local areas in order that the amount of water coming in contact with the'fabric may be kept downto a 40 minimum. Due to the labor involved, this operation is relatively expensive compared to the rest of the process. Moreover, the results obtained depend upon the skill of the worker and, at best, are highly unsatisfactory. I Such spots may in some cases be removed by what is called the wet-dry treatment in which the fabric is first immersed in the cleaning solvent and then, while still saturated with solvent, treated with cold water or a dilute soap solution for from three to five minutes. The presence of the cleaning solvent in the fabric prevents the absorption of suflicient water to cause appreciable shrinking, loss of sizing material or bleeding of colors, but allows the water to come in contact with the soluble spots suiilciently to bring about their solution. This process is tedious, expensive, and may injure a fabric or fail to remove the spots, or both. Obviously, both hand spotting and the wet-dry methods are make-shifts dependent upon artizan skill and judgment. It is, therefore, to be observed at this point that there is no existing process for cleaning fabrics which is inherently adapted to be used on all types of fabrics to remove all types of soil.

It has always been customary (and still is), to clean fabrics made from vegetable fibres such as cotton and linen goods, by washing in soap and water. This process can also be used on some articles of wool, silk and rayon, but very great care is required, and generally speaking, the fabrics made from fibre of animal or synthetic origin, which are adapted to the soap and water washing process, are the exception rather than the rule.

Most of the outer garments worn in this country at present such as suits, dresses, coats, etc., are made from fibres of animal origin, usually silk or wool, or both. Such articles are ruined in appearance by soap and water washing. As a result of the development of cheap cleaning solvents in the last half of the last century, and

as a result of the shifting of popuation to the large urban centers in which more formal attire prevails, the central dry cleaning plant came into being and its facilities became widely available.

The ubiquity of the dry cleaning plants permitted the designers of fabrics to develop a great many new sizing and finishing materials, special weaves, peculiar thread twists, and many new and brilliant dyestuffs, which in cleaning would require the special skill and equipment of the large central dry cleaning establishments. On this account, the so-called dry cleaning process has become a tremendous national industry despite the fact that it does not remove water marks and is inherently adapted to remove from the fabrics but one class of soil, that is, the oil soluble soil, as distinguished from perspiration and other types of water soluble soil.

The object of this invention is to provide an entirely new and novel art, method or process by means of which fabrics are cleansed of substantially all varieties of spots or soil without individual attention to each article treated or the utilization of artizan skill and judgment.

This invention resides in a series of recognitions, concepts and determinations which have required and received verification by large scale commercial operation. upon all classes of fabrics normally tendered to dry cleaning establishments throughout the different seasons of the year during which temperature, humidity, the type of garments worn, and the fabrics employed vary substantially.

These recognitions, concepts and determinations are as follows: An optimum cleaning action on fabrics is provided by a cleaning solvent containing a substantial, predetermined and controlled 'quantity of absorbed moisture. If the moisture be dispersed throughout the cleaning slovent to a very extreme degree, for instance, that degree which is signified by a substantial optical clarity of the solution, then the moisture will not have its usual deleterious effects upon the fibre, the dyestufi,- or the finish of the fabric being treated. In other-words, even the finest silk evening dress will not be injured by this treatment.

Thus, it is possible to'remove the water soluble,

spots or 8011 with a tity-cf M mosa" which is not injurious to the fabric treated,

or vice versa, a quantity'offine'ly" moisture, so small that it does not injure the fabric being treated, has the capacity to remove the water soluble spots and soil. Still otherwise expressed, the invention resides in the concept and determination that an appropriate amount of. moisture appropriately dispersed throughout a dry cleaning solvent,. possesses the desirable o cleaning properties of water but not the disadvantages.

The next feature of this invention, which is rather unexpected, is that the quantity of moisture adapted to produce the best results, should 5 be calculated and controlled primarily in relation to the weight of the fabrics treated, rather than in relation to the weight or quantity of the cleaning solvent used. This is due .to the fact that the fabrics always absorb substantially all go of the moisture in the cleaning solvents Therefore, the quantity of moisture contacted with the fabrics or transferred to the fabrics in the process, is the critical factor rather than the ratio of moisture to cleaning solvent in the bath 25 in which the fabrics are treated.

The ratio of moisture to fabric to be used in practicing this invention must depend upon the moisture tolerance of the type of fabric being cleaned. Themore specific aspects of the ina) vention may be'said to reside in the determination that a useful cleaning action is obtained by agitating the fabrics in a body of cleaning solvent containing about five percent of their weight of moisture and that in many cases, the weight of 35 moisture may be increased to thirty percent of the weight of the fabrics without injury thereto. For instance, silk garments may. be cleaned bytreatment with between five and fifteen percent of their weight of moisture, though approximately ten percent is recommended for most large scale commercial runs which include nu-- merous evening gowns. In the case of men's suits, ten to thirty percent of their weight of moisture may be used in the cleaning solvent,

- though fifteen percent seems to produce the best average results on a batch of winter suits collected from a high class suburban neighborhood. It is obvious that if a fine satin evening dress were treated in a bath in which water and naphthe. were simply churned up together, the dress would become hopelessly water spotted because of large drops of water absolutely saturating the dress in many local areas. Such an undesirable effect diminishes in proportion to the fineness of 5,3-

, fabric in a very damp climate, for instance, on 05 the seashore.

This new process'in which a fabric is treated with and takes on between five and thirty percent of its weight of moisture under normal conditions, (a large group of fabrics being churned 70} about in a container of cleaning solvent and moisture), results in the removal from the fabrics of water soluble soil such as syrup spots, perspiration marks, soft drink spots, and the like,

as well as all oily or greasy soil. Moreover, water 15 spots disappear from the fabric and many types of finish, in general use at present, seem to be not only completely restored and renovated, but improved by this treatment, so that the fabrics look as well or even better than they did when new.

In view of the fact that moisture does not admix readily with the cleaning solvents in common use at present, absorbefacients must be used-(these will be described at a later point).

While the moisture for the first batch of fabrics may be added to the cleaning solvent directly with the absorbefacient, it is believed to be better practice and more in conformity with the spirit of this invention first to add the absorbefacient to the cleaning solvent and thereby create in this cleaning solvent the capacity to absorb the substantial and requisite quantities of, moisture in a state sufiiciently fine and dispersed as not to be injurious to the fabrics to be treated. Then the desired quantity of moisture may be determined and added for each batch of fabrics treated. This step is termed humidifying the cleaning solvent.

It is recommended that the cleaning solvents be constituted water absorbent for the maximum amount of moisture requisite for the impending operations. If this be done, then it is not necessary to adjust the ratio of .absorbefacient to cleaning solvent for particular or unusual conditions which may arise.

In commercial operations, each batch of fabrics to be cleaned is weighed. Generally speaking, fifty or sixty pounds of fabric are considered the maximum load for about fifty gallons of cleaning solvent. Then moisture is added to the cleaning solvent, the amount being based upon the weight of fabrics being treated. In this connection, attention should be paid to the humidity of the atmosphere which normally determines the percentage of moisture already in the fabrics. Likewise, it is necessary to take into account the nature of the fabrics being cleaned and the degree of soil.

It is obvious, by a. large amount spots or soil, require of course, that fabrics affected of exclusively water soluble treatment with larger quantitles of moisture to effect removal than do fabrics having a small amount of soil of this type. when men's rough clothes or the like are being treated, it is possible, if desired, to incorporate so much moisture either before the treatment or during the treatment, that the cleaning solvent becomes murky without injuring the fabrics,

though in the case of ladies fine silk dresses and articles of like nature, injury is almost sure to occur if the dispersion of moisture be coarse. It

must be remembered, in this regard, that the optical properties of the solution are mentioned solely for the purpose of indicating the degree of.

subdivision or dispersion of its moisture content,

. and that these optical properties have no merit or virtue in and of themselves.

In many climates and cases it is desirable to dry out the fabrics before they are treated, as this step permits the transfer of a larger quantity of moisture to the fabric and hence provides a greater cleaning effect for a given final moisture content of the fabric in question. For instance, if silk garments are being treated and the final moisture content is substantially over fifteen percent, then'difiiculty is often experienced in the pressing room because of wrinkling. Such garments, however, can be entirely satisfactorily cleaned and pressed first by drying them out, then treating them with about ten percent (based on the weight of the fabrics) of moisture incorporated in the cleaning solvent.

The preferred process, as a series of steps, comprises: first, drying out the fabric to be cleaned, if necessary. Next, the fabrics are weighed. Next, they are given a preliminary dip in a straight solution of cleaning solvent to get off the worst of the dirti'and saturate .the fibres with cleaning solvent; Next, moisture is introduced into a second batch of cleaning solvent to be used forthe crucial treatment, the amount of moisture used being approximately equal to between five and thirty percent of the weight 'of the fabrics being treated. Ten percent is recommended for fine silks and fifteen percent for men's suits.

After this the fabrics are agitated and churned about in this cleaning bath for a period of between fifteen minutes and half an hour, depending upon the fabrics and their condition. It is highly desirable to filter the cleaning'solvent during this cleaning process, in order to prevent dirt particles being loosely deposited upon the fabrics as they are removed from the bath. In view of the fact that most of the filters in use for this purpose do not permit moisture to pass through them, it is recommended that this filtering be confined to approximately the last quarter of the treatment inasmuch as by that time substantially all of the moisture present has been absorbed by the fabrics being cleaned.

It is of great importance that the absorbefacient employed in the process have the capacity ern, well-equipped dry cleaning plants, in practically all of which filtration during treatment is standard practice. The absorbefaeient, therefore, must form in the cleaning solvent a stable, permanent solution which will pass the filters, will notsettle out, or change chemically or physically in such wise as to lose its requisite colloidal properties.

The fabrics are next given a rinse in cleaning solvent after which they are dried and subjected to relatively routine handling. The filtration of the cleaning solvent containing the absorbefacient may be continued after the removal of the fabrics until the cleaning solvent is clarified to the desired extent. The cleaning solvent is preferably agitated but not passed through the filter during the addition of moisture for the next batch of fabrics to be treated. As pointed out previously, the amount of moisture added must be predetermined and calculated in relation to the weight and nature of the next batch of fabrics. After the cleaning solvent accumulates too great an amount of oil soluble soil or contamination tov substantial quantities of moisture in a state of subdivision so fine that the solution is substantially optically clear; chemical inertness towards all varieties of fibres, dyestuffs, sizes and finishes; physical and chemical stability.

One absorbefacient adapted to constitute a cleaning solvent of the nature disclosed, comprises mahogany sulphonic bodies of the type recovered from the oil layer of A layer in the refining of white oil and the like by the use of sulphonic acid and sulphur trioxide. For instance,

these sulphonic bodies may be of the type described in the United States patent to Devine, No. 1,493,111,1sued May 6, 1924.

While it is convenient to use mahogany sulphonic bodies in the form of sodium salts, theacid may be used where desirable, or various other salts such as potassium, ammonium, triethanolamine, or thelike may be employed. I In fact, the utility is provided by the colloidal power of the acid radical and not by the basic radical constituting the salt.

Generally speaking, mahogany sulphonic bodies may be used in quantities such as between three and six percent of the weight of the naphtha constituting the dry cleaning solvent. When desirable, oleic acid may be used in combination with the mahogany sulphonic bodies to accelerate the tendency of the solution to absorb moise ture. A specific absorbefacient which has been found to be highly useful for large scale commercial operation is:

. Per cent Oleic acid 25 Naphtha 25 True mahogany sodium sulphonate 50 A solution oi 6% of this absorbefacient in a cleaning solvent has been found to be highly suitable for day-in and day-out commercial operation.

Great care must be used in employing this invention with chlorinated cleaning solvents to avoid the formation of harmful quantities of hydrochloric acid and therefore throughout this description the invention has been disclosed in relation to the equipment of an open, naphthaprocess plant, though it must be understood that other types of equipment and plants may be used with appropriate minor modifications well within the skill of the art.

Having described the invention, I desire to be limited only by the following claims: 6

1. An absorbefacient for a dry cleaning solvent,

said absorbefacient comprising substantially 50% true mahogany sodium sulphonate, 25% oleic acid and 25% naphtha.

2. A method of removing oil soluble and water soluble soil concurrently from.fabrics of a type normally injured by water, said method, comprising, treating the fabrics with a liquid comprising dry cleaning solvent and relatively small amounts of oil soluble mahogany sulphonic bodies of the group consisting of the acids and salts and water, the amount of water present being within the moisture tolerance of the fabrics, the amount of mahogany 'sulphonic bodies being adapted to disperse the water to such a degree that it is not injurious to the fabrics being treated; and agitating the fabrics in said liquid until the fabrics have absorbed substantially all of the moisture from the solvent.

3; A method of removing all soluble and water soluble soil concurrently from fabrics of a type normally injured by water, said method, comprising, treating'the fabrics with a liquid comprising dry cleaning solvent and relatively small amounts of oil soluble mahogany sulphonic bodies of the group consisting of the acids and salts, oleic acid as an accelerator of dispersiomand' water, the amount of water present being within the moisture tolerance of fabrics, the amount of mahogany sulphonic bodies being adapted to disperse the water to such a degree that it is not injurious to the fabrics being treated, and agitating the fabrics in said liquid until the fabrics haveabsorbed substantially all of the moisture from the solvent. l0

' WARREN T. REDDIFSH.

DISCLAIMER 2,024,98l. Wan'en T. Reddish,

CLEANING.

1940, by the asslgnee,

Hereb enters this disclaimer of claim [dfieial .9, 1.940.]

P t t d t d fi i Ohio. claim a en a e ecem' or 17, 1935. Dis Y Emery Indusm'es, 1m. er filed Ansonnnmcmmron Dar 2 of the patent.