US2717824A - Method for removing water-soluble stains in dry cleaning garments - Google Patents

Description

United 2,71 7,32%- Patentecl Sept. 13, 1955 METHOD FOR REMOVING WATER-SOLUBLE STAINS IN DRY CLEANING GARMENTS Floyd N. Avery, Princeton, lll.

Application September 18, 1951, Serial No. 247,188

6 Claims. (Cl. 8142) No Drawing.

deleterious effects of water immersion. In both systems of cleaning it is common to utilize emulsifiers or soaps which borrow soil dissolving properneither a dry nor wet solvent action on soilage. either solvent but is media by emulsifying agents in the system being employed.

The wet washing operator is concerned with the emand improved effects The dry cleanin because soilage depends upon the dry cleaners use of Water.

It is such an unfortunate universal belief cleaner shall only employ those methods which are dry that any damage or dissatisfaction is considered a deviathat the drytates atentOfilice I plaints originate in the tion and malpractice of the expected service. This may involve controversy, personal and sometimes legal, that involves trouble and costs to the dry cleaner.

dry solvent Washing process in suitable soaps. It is also emulsion that are brushed and water alone on a spot.

Spots and stains remaining after dry cleaning are treated by a skilled application of Water and with care to cause the least possible cal condition.

age to the articles being cleaned.

The customary procedure for this Wet Washing is well known. The garments are immersed in water, soap or detergent being added, and squeezing, brushing and other mechanical manipulation are employed to loosen or remove the soil. It is also'necessary to rinse soap and soil from the fabric and the use of acid sours may be necessary to counteract the alkaline soap action 'upon the fiber and color. All of this wet handling naturally distorts made up garments beyond the possibility of original restoration in the ensuing pressing or finishing operation. 1 t

The difliculties encountered in Washing operations of the above type are numerous. The following factors are of extreme importance; Water temperature and softness, alkalinity of the soaps or other wetting agents, proper rinsing, and use of sours and their removal.

impossible to overcome. All of this work not only adds to the costs but also to the dissatisfaction of dry cleaning customers since a vast majority of all dry cleaning comwet cleaning department.

More specifically, during this wet operation dyes may be affected and major or minor changes of shade may result. Patterns may The action of soap may full or thicken the material, and matting or felting and disarrangement of the nap and body of wool may result. Shrinkage of wool is not uncommon unless carefully handled. Abrasion or scarring of a satin finish is not uncommon.

The general physical condition of the garment may be altered. Water soluble sizings are naturally removed of sizing is necessary to give the same handle, stiffness, etc. Linings, interlinings,

facings and scams become disarranged and never return to their original shape or position. Bias sections and seams are especially liable to a permanent distortion. Gathers, puffs and fancy arrangements of the cloth cannot be restored by stretching if they are shrunk. Padding becomes matted soggy and lumpy. All raw edges such as holes, tears and seam edges fray with a noticeable loss of original physical condition. Fabrics may become damaged because they are weaker when wet in water. Rayon may lose 60% of its strength when wet. It is noticeable that the seams of some linings fray and give way when wet, requiring resewing. Metallic attachments or trimmings may rust and stain the fabric. Many buttons lose their beauty and luster, especially pearl. Some buttons bleed or run. Some buttons become warped and sequins may disappear entirely. Any skilled cleaner can detect the garments that are wet cleaned by immersion washing and customers may detect it also.

It is the object of this invention to overcome all of the foregoing disadvantages with which every dry cleaner is now faced. While it is the object of all operations in a dry cleaning plant to avoid wet cleaning and the disadvantages thereof when it is found that it must be done this invention avoids the present difficulties of this operation. Compared to the other controlled water applications in dry cleaning methods, this method affords control of the wet solvent action to the greatest degree possible in the required wet processing. There is no necessity for the immersion and handling of the articles in ordinary washing. The control and avoidance of the effects of immersion wetting are more important than the detergent powers which reside largely in the solvent powers of water alone.

This control is accomplished by the degree of wetting, keeping the garment in shape as much as possible, the elimination of squeezing, and the elimination of rinsing. The operation becomes possible only by the selection of a proper assistant or soap. Emulsification, surface action and penetration help dislodge the dirt; and, since the assistant or emulsifying agent employed must be soluble or highly dispersable in common dry cleaning solvents, rinsing by immersion in water baths is completely eliminated. I A further control lies in the fact that textile fibers have an adsorption factor for oil or the fatty part of the soap molecule and, when adsorbed, it protects both dyes and fibers. Since it is not necessary to remove it with an alkaline reaction, as in washing with ordinary soap and water, the protection afforded remains established through the entire cycle of wet cleaning until the soapy agent is removed by rinsing in dry solvent. Bleeding or running of colors is seldom encountered in contrast to ordinary soap and water where it is usually encountered due to the alkaline ions.

The agents employed in this invention may be termed a soap as it is being used as a soap though not all emulsifiers which may be used in this invention are soaps. Conversely, all soaps are not alike and applicable in this invention. A superfatted dry cleaning soap is useless for washing in water and an ordinary laundry soap is useless for dry cleaning. So it is also true that an ordinary neutral soap of the alkali metals is useless for the process of this invention. There is no superior detergent action to that of good laundry soap. However such detergency alone is not required because dry cleaned garments have been degreased so strong detergent action to emulsify oils is not required. Penetrating action on water solubles is helpful in softening, loosening or dislodging the dirt which may be insoluble though it adheres to the fabric.

This process is not merely offering a substitute for ordinary neutral wet washing soap on a basis of detergency. Different physical properties are necessary to this process. The most neutral metallic alkali metal soaps are anion active and decidedly alkaline in their reaction. A less active saponification agent than these strong alkalis improves the safety on all dyes and fibers. Sufficient detergency can be secured without resort to these strong alkalis.

Such alkaline water soaps are further removed from use in this process because they do not possess the property of being soluble in dry solvents. After being applied to a garment they can be removed only by rinsing in water. Such rinsing is essential to their proper use.

The agent to be employed in carrying out this invention must possess two essential physical properties found in some emulsifiers. It must be soluble in dry cleaning solvent and dispersible in water. These are hydrophobic characteristics. However a hydrophilic agent can be used which is dispersible in the dry solvent and soluble in the water, providing it leaves no undesirable residue in the fabric. This complete removal seems more probable and easy with the hydrophobic agent and it also gives more protection to the dyes and fibers of the textile in absorption. The hydrophilic agents are wetter in their action though they can be used. They cause more wrinkling than the hydrophobic agents which tend to prevent full wetting action.

Many agents can be selected with these specifications to be used as what is termed a soap in this process. They can also be selected from all groups of wetting agents, such as, for example, anion active, cation active and nonionic wetting agents.

In the anion active group, agents which may be employed formed from fatty acids and amino compounds. Thus, lauiic and oleic acids combined with isopropanol amine can be made hydrophilic or hydrophobic, as desired, depending upon the proportion of fatty acid to amine employed in their preparation.

A metallic soap such as calcium oleate or calcium laurate mixed or dissolved in a volatile agent such as butanol and then emulsified in water with a non-ionic ester has unusual detergent properties.

Duponol 05, a fatty alcohol sulphate has been used effectively in this process.

Nacconal F, a sodium alkyl benzene sulfonate is also appropriate to this process.

' The cation active agents may be employed, though hy-drophilic and only sparingly soluble in dry cleaning solvents. While they are considered excellent products, their disadvantages appear to outweigh their advantages;

The non-ionic agents seem to afford more numerous and superior products, having the required specifications. They are better because they are dissociating. They are polyhydric alcohol ethers or esters", such as, for example, the mono-laurates, mono-oleates, mono-stearates and mono-ricinoleates of ethylene glycol, propylene glycol diethylene glycol, glycerol and sorbitol. Typical agents which may be employed are the following:

Diethylene glycol monolaurate Diethylene glycol monooleate Polyethylene glycol monooleate Sorbitan trioleate Advawet 33, a polyhydric alcohol ester of a high molecula-r weight mineral organic acid. Stearates:

Carbowax 1000 distearate, a stearic acid ester of a polyethylene glycol Diethylene glycol stearate These stearates are dispersible in hot water and form gels. They can be made into liquid soaps with solvents and are somewhat like high titre soaps.

Of the natural products mention should be made of lecithin. It is 'useable in several grades if made hydrophilic enough for dispersion in water.

A pine oil made solubilized with glycol is an effective agent.

The foregoing and many in use and it is evident that a large variety other agents have been tested of compounds can be selected which meet the required specifications.

It should be noted that volatile oil solvents can be added to the compounds and give an increase in detergent powers as is done with ordinary soa should it be desired. The emulsifying agents employed in this invention including those specifically identified above are either soluble or highly dispersible in the common industrial hydrocarbon and halogenated hydrocarbon dry cleaning solvents; such as, for example, benzine (petroleum naphtha), benzol and carbon tetrachloride.

It isnatural to view the matter of soil removal as a chemical reaction. However the fact is, that so far as this invention is concerned, chemical action is to be avoided so far as possible along with changes which may be caused by water alone. Preservation of the physical condition of the garment is the object, and not chemical action. Though involved'withjchemical composition of the agents the work performed is entirely physical in its nature. There should be no-physical change which is the indication of chemical reaction.

To employ this process, garments or articles to be wet cleaned are placed on a board or table and spread to maintain them in as unwrinkled a condition as possible. In turning or rearranging to expose other portions they should be spread out;and remain flat. With these precautions the articles are given the wet treatment of this invention while the normal undistorted shape of the garment is maintained. 1

in the preparation of the water solution for spraying, 0.1% to.5.0% solutions or dispersions of the'special soap or emulsifier, undiluted, described above are suitable for average use and a concentrationof 1.0% of the undiluted active. surface agent is. preferred in the average application. In no case is there sufiicient agent added to create an emulsion as is used in ordinary prespotting in the dry solvent washing operations.

The wet solution of selected special soap emulsifier in water-is applied to the textile article to the degree found necessary-to loosen, dislodge or dissolve the soilage. It

may be appliedwith a brush, sponge or tampons. Motor driven brushes or saturated pads which press the liquid into the fabric could be used. In the preferred embodiment of this invention a hydraulic spray nozzle is employed that delivers about 24 ounces in a minute at 50 p. s. i. The areas treated are brushed or padded as described above afterthe wetting or dampening to loosen or dislodge dirt attached to the fabric. Auxiliary aids in removing stubborn spots can be employed during this treatment if compatible with the agent used. This can be brushing with cleaners solvent in heavily soiled areas, application of steam to release difi'icultly soluble substances or the application of a more concentrated emulsifier solution to embedded soil as at the heels of trousers or the hems of skirts.

On some articles it is possible and advisable to make a very saturated application as on the knees of trousers which are soiled from perspiration. On a few items the spraying will be a light mist. In this procedure it is possible to control both the physical shape of the article being treated and the amount of wetting to a greater degree than is possible when immersing in a water bath.

After treatment the excess water is removed. This may be done in several ways; such as, for example, with a chamois pad or by vacuum; and, if carefully folded, the

articles can be hydroextracted in a centrifuge, which isreadily available in all cleaning plants. This should be done at low speed and only sufiicient water need be removed to prevent the articles from dripping. I

This completes the wet treatment usually given wet cleaned garments. Variations will be given in the examples which follow. The drying will be done with the consideration usually accorded wet cleaned articles and with which the experienced cleaner is familiar. There is,

however, one advantageous exception. In drying ordinary .wet cleaned garments by known wet cleaning methods, natural air dryin'g'is preferable to heated air in the process. However the softening and neutral oily nature of the special soap employed in this inventiondrying in a heated dry room without the harshness result-;

ing from such drying of ordinary Wet cleaning. This permits hastening of the process. rinsed from the fabric by dry cleaning solvent before finishing, which removes with it all loosened and .dis-

lodged soil, but this is not always necessary.

The beneficial effects of this process may possibly be explained by thefollowing theory. It is known that it is the character of wetting agents orsurface active dispersed molecules to be drawn into a media in which they are dispersed by the solvency or attraction of one portion of. a molecule of an agent in or for the media. The portion,

of the molecule not attracted but, in fact repelled is trying to escape from the media. It is a dispersion instead of asolution because one portion of the molecule is not soluble but held in the media by the other part of the molecule...

It is active at the surfaces in its attempts to find a more favorable attachment. In its attempts it is easy to accept, the attachment to the molecules of fabric or dirt preferentially wet by that portion of the molecule instead of the media. It follows that, in a dry cleaning solvent media, water audits solubles are attracted to those moleculesor surfaces preferentially wet by them instead of the volatile oil solvent. ;In a water mediathe molecules or surfaces; preferentially wet with oil attractthe oil and its solvents.- As an example it has been a commonvpractice to oil textile fibers increasing their strength and pliability before weaving or spinning. This is usually done by an oil or an oildispersed in awater emulsion from which the fibers adsorb the oil. This is removed after the weaving by a scouring process.

Dirt or soilage is either soluble in solvents or preferentially wet inthe same manner as the fibers. In this process solids are coated with the penetrating and wetting.

agent. Their attachment to the fabric is by an oil soluble bond v or molecules which is soluble or removablev by volatile dry cleaning solvents. The soilage has been rephased into a condition where it is removable by'a solvent that-it formerly resisted. Soil which is in an oil phase-is always removable in the dry volatile washing process.

.All'dry cleaned fabrics contain water soluble materials which would be rinsed out in water. Some of this is essential to the character of the fabric and, when wet, such materials are naturally dissolved. If a suiiicient quantitybythe capillary action or traveling of the water to a point of evaporation from the fabric. The solutes present remain in an accumulated deposit and these produce streaks or swale marks. This invention overcomes this difiiculty, when it is apparentthat it may occur. The fabric after the wetting or dampening process, is immersed and slightly agitated in the dry cleaning volatile solvent. This solvent preferentially wets those surfaces preferentially wet by oil; and, forming a slight emulsion with the agent, it stabilizes the water, preventing capillary action from carrying the remaining water solubles to a point of evaporation and depositing them to form a streak. The

preventing streaks.

water solubles are uniformly distributed and established This same principle applies to brushing the edges of wettreated areas with solvent to prevent riugsf Ex perienced cleaners will recognize when this solvent treat-- ment of wet articles is required.

The following are examples of work that may be done'by this'process, which is quicker and safer, and produces superior results. Other procedures may be employed within the teaching of this invention accordin to the judgment of the individual cleaner.

The agent is usually,

Example 1 YA garment. soilcd with water-soluble and hydrocarbon insoluble soil may be relieved of the soil by ordinary washing in which the "entire garment is immersed. But the.

effect of suchkxtensive 'water exposure i's'bad for the taining as little an /3% of thefwettinghgent; With amounts up to 5% a'sati'sfactory-removal can be achieved with a little less wetting. The most convenient concentration for all'around 'use appears to be about 1% For very heavily "soiled" areas'it becomes necessary to get the fabric dripping wet, but for ordinary cases only from one-half to one fourth that much liquid is needed. But in every instance the garment is kept spread out on a table or the like, so that the shrinkage and irregular distortion resultingfrom immersion is completely avoided. The dripping wet condition is needed for garments matted with blood, mud, 'or' animal excretions, and the operator can readily learn aftcr's hort experience to exercise good judgment in applying the'right amount. A heavy spray capable of delivering about 24 'counces per minuteof liquidis best, and in any'eventa'relatively slight'dampening of substantial areas adjacent to the soiled area results from theuse of a spray'and'is advantageous rather than otherwise. An excess of liquid above the minimum necessary to accomplish the desired cleaning function does no harm to the garment.

After the garment is moistened with this solution it is brushed enough to agitate and, disturb the individual fibers gently, and distribute the liquids thoroughly through the structure of the fabric.

' The amount of brushing va'ri'e's with the degree of contamination. I

The garment is then allowed to dry and is subsequently dry cleaned by a conventional v'ol'a'tile dry cleaning sol vent in the conve-ntional way. This will remove the stains with a high degree of effectiveness. to. be that the dissolving'of these stains'in the moisture transfers. the material of the stain into such a relationship with the. wetting agent (whichremains in after the water has evaporated) that the subsequent dissolving of the wetting. agent by the non-aqueous solvent carries the water soluble stain with it. And, .of course, the conventional dry cleaning takes out the soilage soluble in the drycleane ing solvent.

Example L I In treating wool trousers, a type of garment which' usuallyrnust be wet washed'by complete immersion in aqueous alkaline soap solutions owing to heavy soilage and perspiration stains, the trousers are placed on a flat surface-and the pockets arranged in their normal position. A light spray of. a'colloidal dispersion in water of diglycol Ian-rate comaining.2%. by weight-of this ester may be applied. to. the soiledareas; of the garment and heavily soiled areas or areas thereof stained with perspiration may be. sprayeduntil well wet withthe emulsion. The latter areas may be brushed or padded to dislodge and emulsify the soil Thesepperations may be repeated on the other side'df thefgarrnent. The garment is folded lengthwise and thejexcess "water. removedb'y centrifuging at low speeds. The heavily soiled areas may, after spraying, be briefly dipped in a dry' cleaning solvent to avoid the formation of streaks. After the removal of the excess water the garment may then be immersed in a dry cleaning solvent. Other wool garments; such as, for example, dresseg sweaters and coats may be treated as above described. i

I believe the reason- 8 Example 111 Rayon trousers have been treated by the method described in Example I above. However, in handling garments of this type they should be measured prior to processingin order that finishers may restore them to size.

Example IV A garment of corduroy of the type wherein a pile finish is secured to a mesh fabric base by a glue size on the reverse side may be treated by this process whereas wet washing with aqueous alkaline soap solutions dissolve the sire and ultimately destroy the fabric. A garment of this type of material may be placed on a fiat surface and lightly sprayed with a colloidal dispersion in water of an isopropyl amine oleate soap containing 3% by weight of the soap. The garment may then be dry cleaned without first removing the water and then dried in a cool tumbler.

Example V A garment of Palm Beach material is ordinarily Wet washed but, if a dry cleaned appearance is to be retained, this process may be employed. Such a garment is placed on a fiat surface and lightly sprayed with a colloidal dispersion in water of diglycololeate emulsion containing 2% by weight of diglycol oleate until the soiled surfaces are slightly moistened. If necessary at spotting operation may be performed. The garment may be extracted to remove excess water, if desired, and thereafter immersed in a dry cleaning solvent. Upon removal from the latter the garment may be extracted, dried in a moderately warm tumbl'er and pressed.

- Example V I Dresses of silk or rayon materials may be treated by the method described in Example 1V above with the exception that normal air drying is preferred.

Example VII Windbreakers and raincoats of rayo n and cotton retain soil tenaciously and the soiled areas thereof should be thoroughly sprayed with a colloidal dispersion in water of diglycol laurate containing 2% diglycol laurate. The garments are thoroughly extracted to remove excess Water and then placed in a dry cleaning solvent for from 1 5 to 20 minutes. The garments are then rinsed in dry cleaning solvent and dried in a tumbler.

Example VIII A coat or vest may be treated in the manner described in Example 1 above. Such articles are difficult to Wet wash by immersion in aqueous alkaline. soap solutions since the manipulation of the garments in such solutions causes them to loseshape. This may be avoided by placing such garments on a flat surface and applying a spray Examplev IX U The removal of blood stains is accomplished by spraying a 3% to 4% by Weight of diglycol laurate colloidally The garment is.

dispersed in water on the soiled area. allowed to stand for about one-half an hour and the soiled area is then brushed. Thereafter, the area may be sprayed with the emulsion again and allowed to dry. The soil is thus completely broken down and the garment may be dry cleaned.

Example X Dark cotton. pants have an oily finish to provide. a rich. appearance. This may be preserved bythis method Example XI A sheepskin coat may be cleaned by the method comprising this invention. Such articles have only been dry cleaned in the past since the wet washing thereof in aqueous alkaline soap solutions was impossible due to the nature of this material. of 1% by weight of Example XII of neckties has, heretofore, been an ex problem. By this invention, a 2% The spotting tremely difi'icult water containing 1% weight of diglycol laurate. If the leather is dyed it should not be brushed with dry cleaning solvent while wet with emulsion. A natural finish leather may, howin a single step, the most advantageous features of each of the separate steps of spotting, wet washing by immerments may be pre-wetted by this method and the mechanical action of scrubbing obtained in the dry cleaning machine.

10 This application is a continuation-in-part of application Serial No. 604,539, filed July 11, 1945, now abandoned.

I claim:

1. The method of dry cleaning a garment having areas soiled with colloidal disby weight of the mono- References Cited in the file of this patent UNITED STATES PATENTS 1,623,791 Kara-Joseph Apr. 5, 1927 2,009,365 Wait July 23, 1935 2,052,025 Harris Aug. 25, 1936 2,052,891 Merrill Sept. 1, 1936 2,131,137 Franz Sept. 27, 1938 OTHER REFERENCES Bennett: Ind. Chem. 8, 223, 224 (1932). Copy in Scientific Library.

Hubbard: Instructor in Garment Cleaning, National Association of Dyers and Cleaners, 1924, pp. 73, 74, 123, Copy in Scientific Library.

National Cleaner and Dyer Book of Technical Notes (1922), Dowst Brothers Company, Chicago, pp. 77, 89, 150, 151. Copy in Scientific Library.

Glyco Chemicals Bulletin, 26 Court Street, Brooklyn, New York, 1944, p. 11. Copy in Div. 64.

Claims (1)

1. THE METHOD OF DRY CLEANING A GARMENT HAVING AREAS SOILED WITH WATER SOLUBLE SOILS WHICH CONSISTS OF THE STEPS OF SUPPORTING THE GARMENT AND MAINTAINING THE NORMAL SHAPE THEREOF WHILE SUPPORTED, APPLYING TO THE AREA OF SAID GARMENT SOILED WITH WATER SOLUBLE SOILS WHILE SAID GARMENT IS SUPPORTED A SMALL AMOUNT OF COLLOIDAL DISPERSION OF AN EMULSIFYING AGENT SOLUBLE IN HYDROCARBON AND HALOGENATED HYDROCARBON DRY CLEANING SOLVENT, SAID EMULSIFYING AGENT BEING A MEMBER SELECTED FROM THE GROUP CONSISTING OF AMINE SALTS OF HIGHER FATTY ACIDS, HIGHER FATTY ACID ESTERS OF POLYDRIC ALCOHOLS, FATTY ALCOHOL SULFATES, SODIUM ALKYL BENZENE SULFONATES, AND CALCIUM SALTS OF HIGHER FATTY ACIDS, SAID COLLOIDAL DISPERSION CONSISTING OF FROM 0.3% TO 5.0% OF SAID EMULSIFYING AGENT AND THE BALANCE WATER, WHEREBY SAID WATER SOLUBLE SOIL IS DISLODGED AND SUSPENDED IN SAID WATER BY SAID EMULSIFYING AGENT, REMOVING SAID GARMENT FROM SAID SUPPORT WHEN THROUGHLY WETTED WITH SAID DISPERSION AND IMMEDIATELY THEREAFTER IMMERSING SAID GARMENT IN A DRY CLEANING SOLVENT SELECTED FROM THE GROUP CONSISTING OF HYDROCARBON AND HALOGENATED HYDROCARBON DRY CLEANING SOLVENTS TO PREVENT SAID WATER AND WATER SOLUBLE SOIL FROM MIGRATING THROUGHOUT SAID GARMENT AND TO TRANSFER SAID WATER SOLUBLE SOIL AND SAID EMULSIFYING AGENT TO SAID DRY CLEANING SOLVENT WHEREBY WATER SOLUBLE SOIL IS REMOVED FROM SAID GARMENT WITHOUT SUBJECTING SAID GARMENT TO WET WASHING.