US2072332A - Method of dry cleaning - Google Patents

Description

Filed Aug. 12, 19:55

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Patented Mar,

Conad .l artour Edward naraelajroronto, ontario,

Application .August iz, 1935, serial No. 35,832 comms.- ol. ca -3s) My invention relates to a method of dry cleanlng, that is, a process o1' cleaning garments, fabrics, texti1es`,and the like, by means of solvents such as light hydrocarbons, including gasoline 5 and naphtha. and chlorinated hydrocarbons such as carbon tetrachloride or trlchlorethylene and ,like organic solvents.

The instant invention is an improvement over my Patent 1,990,691 of February 12, 1935. 1oA In Patent 1,990,691, I disclosed a process of dry cleaning which enabled both greasy soils and water soluble soils to be removed without the dangers and disadvantages attending the humidifying cfa dry cleaning solution. In the process i5 o1' my patent, I'an able Ato accomplish the results Vby rst rendering the fabrics water repellent and then'subsequently-humidifying the dry cleaning solution.

In practical operation, a dry cleaning bath is go-used for successive batches of clothes. After the dry cleaning solvent has beenv once humldied, `I have found thatrcolloidal vwater is dispersed throughout the solution. This water-is ofsuch small quantity that it is not objectionable in 25 causing clothes to shrink. I have found, how' ever, that' the presence of water has'a deleterious eiiect when greasyf-soils are removed. If it is attempted to remove greasy soils in the presence of water, upon the clothes being immersed' in 3o the cleaning bath, the dirt is first released from the clothes and then is redispersed because of the presence of Water and redepcsited upon the clothes. This results in making thev clothes look hazy and dull. 'rIn order to get perfect dry cleana5 ing, therefore, it is essential that the greasy soils be removed from the clothes and the dry cleaning solution clarilied or iiltered of the greasy dirt by iiltration or the like, before it is attempted to remove the water soluble soils by humidifying the 40 dry cleaning solution.

One object of-my invention is to provide an improved method of dry` cleaning in which the greasy soils and water soluble soils are removed in stages. i5 Another object of my invention is to providea process of dry cleaning in "which both greasy soils and water soluble soils aire removed from the fabrics without the danger of redepositicn. of soil upon the clothes. i0 Another object of my invention is to provide a process of dry cleaning inwhich a dry cleaning bath is alternately humidiiied and rendered substantially anhydrous, and the same bath continuously used for cleaning successive batches of '5 fabrics.

washer.

Other and further objects'of my inventiony will appear from the following description; v In general, my invention contemplates'the dehydrating of the' dry cleaning bath by means of `a dehydrating agent after the water soluble soil 5 agent a natural, hydrous silicate of alumina, known generally as bentonite which has the property of absorbing 'from ten to twenty-uve times its weight of water.

Bentonite may be represented by the formula,

- Alioaesioi-ino' In the above formula, a: may represent any number from 1 to 15 depending upon the dryness ofthe sample. Y The amount of chemically combined Water, however, does not ordinarily exceed 2H2O. Bentonite, however, has very little chemi, cal aflinity for water. It is no more hygroscopic than any inert, powdered, argillaceous material. Bentonite, however, does have a great physical avidity for water in liquid form. VIn. the formula given above, the alumina may be replaced to a considerable extent by iron, lime or magnesia and, to a very limited extent, by alkali.

In the accompanying drawing, which` forms part of the instant specication and is to be read in conjunction therewith;

` Figure 1 is a schematic view showing the ar= rangementof the washer, pump and lter through which cyclic ilow of the solvent occurs.

Figure 2 is a chart showing the stages of my process in outline.

More particularly, I may employ as a dry cleaning solvent any of the well known agents such as naphtha, gasoline, carbon tetrachloride, trichlorethylene, and the like. The system is 'rst lled with dry cleaning iiuid. The pump is started and dry cleaning fluid is circulated from the washer to the pump, through the iilter and back to the washer. Filter aid, which may be fullers earth, diatomaceous earth, or the like, is introduced into the circulating ring of the fluid. It is understood that the filter aid may be introduced at any suitable point into the ring. l A. convenient place for its introduction is into the The lter ai'd is caught upon the leaves oi th'e iilter, pre-coats the lter and precludes its becoming clogged readily. 'I'he amount of nely divided bentonite is then introduced, together .with someedaiuonai suer aid. Bentonae may 55 be used alone, if desired. Instead of bentonite,

I may employ other dehydrating agents, such as calcium chloride and the like, either alone vor with bentonite. However, ifthe original dry cleaning uid is not substantially anhydrous, the bentonite, in absorbing water from the dry cleaning uid will tend to clog thefilter. The addition of bentonite along with a diatomaceous earth which is highly porous will assure that resistance to ilow will not build up unduly. The Icirculation is continued to permit any Water which might be present to be taken' out of the dry cleaning fluid by the bentonite which .is caught upon the leaves of the lter. The dry cleaning iiuid is then ready for the incorporation therewith or a material capable of rendering fabrics water repellent. This material may be, as disclosed in my Patent 1,990,691, paran wax, glycerides of various`4 fatty acids of Vhigh molecular weight, various naturally occuring or synthetic aliphatic esters, or mixtures-thereof. It is only necessary that the materials employed are y stable and do not have objectinable odor. To

assist in the dispersion of the water repelling 25 material, a dispersing or coupling-agent'such as ethylene glycol, monobutyl ether or4 the like may be employed. Thedry cleaning bath may contain from ve percent to fifteen percent by weight of the water repellent material. A solution of about eight percent by weight of dry cleaning solvents has been found to be nvery eiilcient in practice.

After the material has been.added, the pump is started to thoroughly incorporate the material with the dryI cleaning bath. Inasmuch as the water repelling material is `soluble in the dry cleaning iiuid, it will form a solution 'which will pass through the filter easily. The bath is then ready for the reception of the clothes to'be 40 cleaned. These are introduced-into the washer and the pump is started, producing the circulation of the dry cleaning fluid. The dry cleaning will dissolve the greasy material and release dirt and soil'from the clothes. As rapidly as the soil is 45 removed, it will be deposited upon the leaves of the lter. If desired,'lter aid may be added;

with the clothes to insure that the matter released by the clothes does not tend to clogv the4 lter and thus build up resistance to the flow. 50 At the time the filter aid is added, the bentonite may be also added. In practice, I have found that a. mixture comprising about seventy percentby weight oi` calcined diatomaceous earth such as that sold under the trade name of Hyiio 55 Supercel, and about thirty percent by weightof bentonite, makes an Aeillcient agent. The ma' terials are intimately mixed and added in proportion to the weight of the. clothes. I have found that the amount of the above mixture to 60 be added should be from one half to one percent of the weight of the fabrics being cleaned. .inasmuch as the solution is anhydrous, the bentonite will merely be caughtupon the leaves of the lter, while the filter `aid will prevent the dirt 5 released from the clothes clogging the lter and building up pressure.

The circulation is continued until all the solids are removed from the solution and the clean solution is circulated. This can bereadily de- 70 termined` by sight glasses which are usually provided in dry cleaning systems -oi the type described. In practice, a time interval of about ten to fteen minutes is necessary in order to remove all of the greasy soils from the clothes and main# 75 tain a clear circulating soli1.l ',i )ll',l The bath is aorasse now ready fo'r humidifying. It is understood that dry cleaning fluids will not touch water soluble.

soils such as stains occasioned by sugars, starches, and the like. In order to remove these soils. water is necessary. Due to the fact that'the fabrics have been rendered water repellent, the amount of water added is not critical. It is unnecessary, however, to add an excess of water.

In general, the amount oi. water to beadded may be gauged by the )condition of me fabrics. 1fthe fabrics are extremely dirty, about thirty cubic centimeters of water could be added for`each pound of fabrics. If the fabrics are moderately clean, fourteen cubic centimeters of water per pound of fabrics is adequate to remove water soluble soils. 'I'he water may -be added in any suitable manner, at any suitable place in the circulating ring. For every three parts of water,

it is advisable to add one part of a dispersing or coupling agent to assist in the dissemination of the water through the dry cleaning bath, thus humidifying it. Such materials as alcohols, tri- Lethanolamlne, and cyclohexanol are adapted to be used as dispersing agents. A convenient place for the introduction of the water isinto thel washer. The circulation is continued and the action first is 'to disperse the water through the bath, enabling it to dissolve the water soluble soils. f

As the dry cleaning bath passes throgh the filter, which it will be remembered has been coated with a quantity of bentonite, part of it is. absorbed by the bentonite. Each time the bath comes in contact with the bentonite, a portion ofthe water is absorbed. The circulationis continued a short time after itis optically clearto' insure that all of the water is absorbed from the dry cleaning bathso 'that it will be ready to receive the next batch of clothes. It willlbe observed, of course, that the dehydrating may be carried on after the clothes are removed and'A before the next batch is added.

It will be obvious that my improved process has' many advantages. In prior practice, the moisture in solution in colloidal suspension was detrimental to the cleaning of the next batch of clothes,

. fore it `was necessary,before a fresh batch of clothes was entered into the system, to determine the quantity of water in order to avoid adding an excess of water during the second ge of the process. This was done' by extrae g one hundred cubic centimeters of the solution and distilling it in the laboratory and centimeters of the condensate Whichcameoff.

g the' amount of water in the `rst ten or twenty cubic The number of cubic` centimeters .of water willrepresent the percentage By substantially bath before entering a fresh batch of clothes, the

of water in the bath.

pletely dehydrating they danger of redepositing soill upon the clothes due l to the presence of water and thus obtaining dull or hazy work is greatly lessened. Perfect control of the amount of water in the solution obtains in my improved process since a fresh batch of clothes is always charged to a substantially al1-V hydrous bath. In the process pt my patent. a.

certain amount of water was absorbed by the filter aid, which has the property of absorbing about its own weight in water. The colloidal water, however; passed through the filter with ease and was always present in the bath. While this did not have a deleteriousv eiect uponthe clothes from the standpoint of shrinking them', it did cause redeposltion o! the soil amas:

and, it a 1111er quantity oi.' watenwerefpresent, the ;elothes would look dull. By the use of bentonitafl am enabled to render a dry cleaningbath, which-has been humidiiled. substantially anhydrousi'thuszobtainingsuperior results. l 't It will be understood that certainffatureeand subscomhinations are otutility and may be em ployed without reference to other features and Y sub1-combinations. This is contemplated by and i/wiuan-the scope er. my chimp-rz is umher obvious that various changes-:maybefmade in details within the scope or my claims without' departing from the spirit ot my invention; Itis, therefore, to be understood that my invention is not, to be' limited to the specinc detalls shown and described.

Having thus claim is:

l. A process of dry cleaning inollldln'the steps ot dehydrating an organic solvent, -=1 a material capable of rendering fabric waterrepelient with the -soirventgvashing lfabrics inthe anhydrous solutiontr'remove greasy, -soil and to render the fabrics water-repellent, in-

corporating water vvithsolvent and the fabrics inthe humidiiied solvent to remove water-soluble soil from the'fabrics.

2. s process or dry neming-meinem the bycontactinlz the described invention.' vvhat'l- A moisture repelling properties to the fabric,

3. Inaprocess otdrycleaningin whichasolventcontaining-a material capable of rendering fabric waterfrepellent is circulated through a washing stage-'and a iiltexing stage continuous! torem'ove greasysoiLandthen wateris through the circulating solvent to remove watere soil. the step oi' dehydrating the solvent before commencing the process.

4.' In a process of dry cleaning in which a-.sol-v vent containing a material capable of rendering fabric water repellent is circulated through a washing-stage and a ltering stage lcontinuojusly to remove greasy soil, and then water is dispersed through the circulating-solvent to remove watersoluble soil; the step ot dehydrating the solvent same with bentonite before commencing the process. l

5. A, process o! dry cleaning including thesteps otwashlng'a fabric 1in anhydroussolvent containa material capable oi' rendering. the fabric water-repellent, to remove greasy. soil and impart then addingbentonite to the .dry cleaning solution. then dispel-sing water through cleaning solution to remove water-soluble soil and allowing a suillcient time interval to permit the ben-- togiteto absorbfzhe added water.

. of dry cleaning including the or circulating a solvent containing a capable o! rendering lfabrics waters 1= through fabric,.oontlnuously nitering the solvent, adding'a iilter aid' and'bentonite to the circulat.

ing solvent and allowins'the iilter ald and bentonite to-be caught in the iilter. dlspersing water solvent and continuing circulating thesolvent tlally anhydrous.

, "ARTHUR mann m'n'mn.

until thelsaine is rendered minsten-

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