US2295596A - Soap flake of novel phase composition and process for making the same - Google Patents

Description

. 6 9 u u a 9 a 2 v .r 2 a .6 h DS M 2 o I V. MILLS Sept. 15, 1942.

SOAP FLAKE OF NOVEL PHASE COMPOSIT PROCESS FOR MAKING THE SAME Filed June 12, 1942 C ON DE MSER FLASH amms- HEATER PUMP All?

CONT/N00 US CRUTGHEI? PUMP Bull 05% COOL/N6 AND AG/TAT/NG DEV/CE PRO S FOR MAKI THE S led June 1942 2 Sheets-Sheet 2 Sept. 15, 1942. v. MILLS 2,295,596

' SOAP FLAKE OF NOVEL PHASE COMPOSITION AND AME Patented Sept. 15, 1942 2,295,596 SOAP FLAKE OF NOVEL PHASE COMPOSI- TION AND PROCESS FOR SAME MAKING THE Victor Mills, Ivorydal e, Ohio, assignor to The Procter and Gamble Company, Ivorydale, Ohio, a corporation of Ohio Application June 12, 1942, Serial No. 446,758

(or. 252 sss) 14 Claims.

This invention relates to soap in flake form having a novel phase composition, with resulting improved properties, and to a process for making this product.

Soap flakes for laundry and household use have been made by several different processes. Perhaps the earliest method consisted in slicing framed bar soap into chips or flakes. Later, a much less expensive method was developed, consisting of spreading molten kettle soap in a thin fllm upon the rotating surface of a large water cooled steel roll, scraping off this film after it solidifies, at the same time cutting it into ribbons, drying these ribbons in a current of heated air, and breaking up the crisp dried ribbons into flake form. In a modification of this process shiny translucent soap flakes are made by passing a dried soap base in flake form through heavy calendering rolls and cutting or breaking the resulting sheet into small flakes.

A high solubility rate is a much sought for property in flaked soap products, especially when combined with other desired characteristics such as sufflcient physical strength to resist excessive breaking up and powdering during packing-and shipment. Methods have been practiced for attaining such desirable qualities by regulation of the chemical composition and the thickness of the flakes. My invention provides a different method for attaining these qualities, a method which depends upon modifying the physical structure of the soap.

All of the aforementioned methods of making soaps in flake form, and the variations of these and other heretofore known methods with which I am familiar, produce products in which the soap is mostly in the omega phase, which is a relatively slowly soluble solid soap phase. In any of them which have contained soap in the much more rapidly soluble beta phase, this phase has .been present only to the limited extent possible as a result of its spontaneous formation in the absence of mechanical agitation under the conditions prevailing when the soap cooled from fluid to solid condition, or to the limited extent possible by the mechanical working that takes place under the conditions which exist in making polished or calendered flakes.

A principal object of my invention is to produce soap products in flake form in which thesoap is well over half, and in some cases substantially entirely, in the more rapidly soluble beta phase.

Another object is to make soap products in flake form having increased solution rates because of increased beta soap content as compared with soap products of like chemical formula and comparable form produced by previously known methods.

Another object is to make soap products in flake formhaving increased solution rates because of the novel loosely knit structure that may be produced by the process of my invention, this structure being one which is readily penetrated and disintegrated by water.

Another object is to provide a method for controlling the beta soap content of soap flakes.

Other objects will appear from the following description of my invention.

In its bare essentials the process of my invention comprises transforming soap substantially, and in some cases wholly, to the beta phase by mechanical action, usually after having reduced the moisture content of the soap base substantially below 30 per cent, and then forming the transformed soap into flakes under conditions such that its beta phase content does not revert to a significant extent to the less rapidly soluble omega phase, the processing conditions prevailing during the phase transformation step being so chosen as to favor the production of a loosely knit structure, readily penetrated and disintegrated by water, and to facilitate the subsequent fiake forming operation, as is hereinafter explained. During or following the flake making operation, the moisture content of the product is usually further reduced, taking care that the conditions prevailing during this final drying are such as to avoid reversion of the beta phase. Soap builders may be incorporated either before or after the phase transformation step, if desired.

One form of apparatus suitable for the practice of the invention is shown in the accompanying drawings, in which:

Figure 1 is a diagrammatic showing of a preferred form of apparatus for use in the practice of the instant process, including the steps of reducing the moisture content of kettle soap while still in the molten condition, partially cooling and thoroughly agitating the same, spreading the resulting mass on a cooling roll, removing it from this roll in thin ribbon form, and passing these ribbons through a drying chamber from the end of which the finished product is removed;

Figure 2 is a longitudinal sectional view of the cooling and agitating device shown in Figure 1;

Figure 3 shows a transverse section, taken substantially on the line 33 of Figure 2;

Figure 4 is a transverse sectional view on the line 4-4 of Figure 2; and

Figure 5 is an end elevation of certain structure shown in Figure l.

The characteristics and properties of the beta and omega sodium soap phases and a method of transforming soap of suitable composition into the beta phase are described in my copending application Serial Number 376,399, filed January 28, 1941, of which the present application is a continuation-in-part.

I have found that soap in the beta phase is formed when soap of suitable composition is mechanically agitated or worked while it is being cooled from a hot fluid state through various degrees of plasticity such that its final temperature while being agitated is reduced below a critical temperature which varies with the chemical composition of the real soap portion of the mass and with the moisture content.

The above mentioned critical temperature may be considered as the highest temperature for a given soap at which the amount of beta soap that may be produced therein by thorough agitation, followed by prompt cooling to room ternperature to stabilize the phase composition resulting from this agitation, is just enough to cause a sample of the soap to exhibit the characteristic 2.75 A ring of beta soap when the X-ray diffraction technique described in the aforementioned application is employed. Thorough agitation of the soap at temperatures higher than the critical temperature, followed by prompt cooling without agitation, does not produce in the soap a detectable amount of the beta phase.

I determine the critical temperature by noting the value at which the characteristic beta ring appears in X-ray diffraction photographs of soap samples representing different final temperatures of cooling with simultaneous agitation in the phase transforming step of my process. A more readily available means of approximating the critical temperature is to compare sudsing rates of soap samples representing differential final temperatures of cooling with simultaneous vigorous agitation with the sudsing rate of a similar sample of the soap rapidly cooled from molten to solid condition in the absence of mechanical agitation. In applying this latter test (which is merely indicative, and does not conclusively show the presence of the beta phase) it is, of course, necessary to have the samples to be compared in the same general form, preferably all in solid bar form.

The critical temperature is not the same for all soaps; it varies with changes in the real soap formula (by which term I mean the composition of the true soap portion of the product) and also with changes in the moisture content. For sodium soaps prepared by reducing the moisture content of kettle soap to twenty-six per cent, for example, the true critical temperature is found, by thoroughly agitating soap under controlled temperature conditions, to be about 160 F. when the real soap formula is composed of twenty per cent coconut oil soaps and eighty per cent tallow soaps, and it is about 150 F. when the real soap formula is composed of fifty per cent coconut oil soaps and fifty per cent tallow soaps. For the latter real soap formula the critical tempera ture is about 160 F. when the moisture content is twenty-one per cent. These critical values vary somewhat with changes in the characteristics of the fats employed. In general, for soap of a given real soap formula the critical temperature increases as the moisture content decreases.

Soap in the beta phase is not stable at high temperatures; under such conditions beta phase soap tends to revert spontaneously to the omega phase, or to a non-solid phase, and at the same time the solution rate of the soap, when brought back to its original temperature, decreases. Some of the beta phase soap in soaps of the aforementioned real soap formula, containing about twenty per cent moisture and made by my new process, slowly reverts to omega phase (or reverts to a non-solid phase, and resolidlfies as omega phase) at temperatures above about F., and reverts more rapidly as the temperature is increased. Soaps of higher moisture content may revert somewhat even below 160 F. If heated to temperatures above 200 F. the reversion rate of twenty per cent moisture soap is so rapid that substantially all the beta phase reverts to omega or to a non-solid phase within a few minutes. Under these extrem conditions agitating action does not transform soap to the beta phase. In making soapfiakes by my process it is therefore desirable to avoid subjecting the soap, after it has been cooled with simultaneous agitation, to temperatures high enough to cause substantial reversion of the beta phase, if a product of the highest obtainable solution rate is desired.

In order to facilitate an understanding of the invention and of one method whereby the invention may be practiced, apparatus which may be employed for the purpose is illustrated in the drawings and specific language is used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, the practice of the invention with other forms of apparatus, capable of accomplishing the desired purpose, being contemplated.

Figure 1 shows diagrammatically the various component parts of an apparatus which may be so operated and controlled as to produce the soap of the present invention. This includes a soap storage tank il, a heater I4, 3, flash chamber IS, a continuous crutcher 46, a cooling and agitating device 24, a cooling roll 60 and a flake dryer 6|. It will be appreciated that the several units of the system are so shown in the drawings as to facilitate an understanding of the nature of the equipment and that the relative size of these units as so illustrated is therefore of no significance.

The continuous crutcher indicated generally at 46, which forms no part of my invention, may be any suitable ingredient proportioning and mixing means such as the devices described in Robert V. Burts Patents 2,024,425 and 2,203,980. It will be understood that any other means of supplying molten soap to the cooling and agitating device, and of proportioning and admixing any desired additional ingredients, such as perfume, preservative, builder, air, etc., will serve my purpose.

Turning now to Figures 2, 3 and 4, constituting sectional views of the cooling and agitating device 24, it will be noted that the soap is delivered through conduit I9 into an annular chamber 28 defined by a generally cylindrical drum 29 and a shaft 33, the latter being supported for rotation on the axis of the drum. The drum 29 is formed of heat conducting material, such as metal, and is surrounded by a second cylindrical wall 3| to provide a cooling jacket, a cooling medium being introduced into the annular space 30 surrounding the drum 29 through an inlet port 38, and being withdrawn therefrom through an outlet port 39.

' As is apparent from the drawings, the soap is forced to flow through the chamber 28 in a relatively thin annular layer; excellent results have been obtained in practice by the employment of a shaft 33 and a drum 29 of such dimensions that the thickness of this layer is of the order of one inch or less. A plurality of scrapers 34, arranged as shown in Figures 3 at intervals about the shaft 33, are secured to the latter and positioned to engage and scrape the inner surface of the drum 29. Communicating with the rear end of the drum 29, and preferably affording a continuation thereof, is a generally cylindrical drum 42.

Rigidly mounted within the drum 42 are a plurality of annular elements 32, each of which is provided with a plurality of substantially radial, inwardlydirected arms 39, serving as baffles. shaft 43, forming a reduced extension of the shaft 33; is threaded or otherwise secured to the rear end of the latter and is provided with a plurality of generally radial arms 35, disposed in proximity to'the baffle arms 36 and cooperating therewith to mix the soap and to disperse throughout the mass any added ingredient which may be introduced through pipe 48. From the drum 42, the soap passes through a tapered discharge'housing and is delivered to pipe 49 at the rear thereof. A motor or other suitable driving means may be employed to rotate the shaft 33 and 43, as shown in Figure 1.

The details of the coolin and agitating device disclosed herein form per se no part of the present invention. Devices of this character are disclosed, for example, in the patent to Vogt, No. 1,783,864, dated December 2, 1930, and, its Reissue No. 21,406, dated March 19, 1940, and are merely representative of apparatus which are found specifically suitable in the practice of the instant invention.

The cooling device 24 isprovided with an outlet pipe 49 through which the treated soap massfiows to a plurality of outlet nipples 62 mounted above the feed hopper of chilling roll 60. Thin ribbons of chilled soap are removed from this chilling roll and are passed through a flake drier 6|, in which they are dried to the desired degree, and from which they are conveyed to the container packing operation and broken into flakes.

The chilling roll 60 and flake drier 6|, which form no part of my invention, may be any of the several well know types which are widely used in the soap industry. A drier of the type illustrated in Fig. 9 on page 13, section I, vol. II, of Geoffrey Martin's The Modern Soap and Detergent Industry" (2nd edition) is suitable, although instead of the multiple roll chilling arrangement there illustrated I prefer to employ a single chilling roll with a single feed roll as illustrated in Patent 1,583,484 to Morrison et al.

The operation of the apparatus illustrated herein in carrying out my process will be understood from the following descriptive example.

Sodium soap of tallow mixed fatty acids, in the neat phase, prepared by the usual well known kettle process, and containing about 30 per cent of moisture, is stored in tank ll, Figure 1. It is heated to about 390 F., undera gauge pressure of 250 pounds per square inch or more to prevent volatilization of moisture, by pumping through a closed type of heater l4, heated by high pressure steam or other suitable medium.

The soap is then discharged through a spray nozzle into chamber l5, where it flashes to atmospheric pressure with volatilization of sufficient moisture to reduce its moisture content to about 20 per cent; at the same time its temperature is reduced to that corresponding t the boiling point of soap containing this reduced percentage of moisture, or about 224 F.

This hot molten soap of about twenty per cent moisture content, still in the neat phase, is then transferred by pump or other suitable means into and through the rest of the apparatus under just suflicient pressure to accomplish this transfer at the rate desired. In the cooling and agitating device, while in a thin layer not substan tially greater than one inch, the soap is cooled to an average temperature of about 135 F. at which temperature it has a soft pasty consistency and is well below its critical temperature. The film of soap which is chilled on the inner surface of the cooling jacket is quickly scraped off by the scrapers 34 and mixed with uncooled soap, with agitation. In the apparatus described, I find a cooling medium consisting of water between 35 F, and 65 F. to be satisfactory depending on rate of water flowand finished product properties desired, but cold brine or liquid ammonia, or other cooling medium may be used instead.

The soap then passes into and through drum 42 in which all parts of the mass are thoroughly mixed by the rotating arms or paddles 35 and by clearance between rolls and 64. After traveling a substantial fraction of one revolution of roll 60 the soap film is scored (by short pieces of piano wire, mounted at to form ribbons of the desired width, usually from about one-fourth inch to about one inch, and is removed from the roll by a "doctor knife 66. The ribbons thus formed, 51, fall onto a belt conveyor 68 which conveys them into a soap flake drier, indicated schematically at 6|. In this drier the ribbons pass through currents of relatively dry heated air. The volume and temperature of this air are so regulated, in well known manner, that the product does not at any time exceed about 160 F. in temperature, and that it reaches the product outlet at the rear of the drier with a moisture content of about 10 per cent and a temperature of about to F. The dried ribbons are so brittle that they break into flakes as they are conveyed, for example by conveyor 68, to the finished product packing operation.

The real soap portion of the soap flakes thus made is almost entirely in the beta phase (this being judged by comparing the intensities ofthe characteristic beta diffraction rings with those of a soap completely converted to the beta phase by adequate working under most favorable beta forming 'conditions) as compared with about 30 per cent beta phase in soap comparable in composition but made by the usual well known soap flake making process, comprising chilling kettle soap on a roll and drying the resulting ribbons. The soap, thus made by my process appears to have what I term throughout this specification a loosely knit structure. In any event it is a structure which is readily penetrated and disintegrated by water. The solution rate of soap flakes made by my process is substantially greater than flakes of comparable formula, moisture content. and thickness made by previously known methods.

In another spec fic example of my process and product, sodium kettle soap prepared from a mixture of per cent coconut oil and 85 per cent tallow was reducedto 23 per cent moisture content, was cooled with simultaneous agitation from a hot molten condition to a temperature of about 122 F., was thoroughly mixed with about one-eighth its weight of sodium silicate solution of about 46 B., having a. ratio of SiOz/Na-2O of about 3.0 and a temperature of about 160 F., and the resulting warm pasty mixture was cooled on a water cooled chilling roll, scraped off as plastic ribbons, dried to about eight per cent moisture, and broken up to form flakes. In this modification of my process the silicate solution was introduced into the soap mass in drum 2 through pipe 48, at a controlled rate proportionate to the rate of flow of soap, by means of a metering pump, indicated at 54, driven in timed relation to the continuous crutcher 46.

In standardized solution tests, with fiakes of 0.004 inch thickness and about 4 per cent moisure content in each case, I have found that flakes whose real soap content is twothirds transformed to the beta phase, by agitation while in a pasty condition below the critical temperature of the mass, dissolve in 105 F. water in from one-third to three-fourths the time required by comparable fiakes not subjected to my process.

I find that a cooling device such as I have previously described, having a chilling chamber six inches in internal diameter and eighteen inches long, with free space for soap about one inch in thickness, with a shaft rotating at about 200 R. P. M., and with the jacket supplied with an adequate amount of cooling water at about 35 F., will sat isfactorily cool about 400 to I00 pounds of soap per hour and transform at least two-thirds of the soap to the beta or more rapidly soluble phase, when soap of about to per cent moisture content, and having a real soap formula consisting of per cent sodium soaps of tallow mixed fatty acids and 15 per cent sodium soaps on coconut oil mixed fatty acids, is supplied to the cooling and agitating device at a temperature of about 220 F. to 223 F. and is removed from the cooling chamber thereof at a temperature of about F. to 130 F. Under these conditions agitation for as short a period as one minute or even sistant to flow. It is believed that this is the temperature at which the last non-solid soap in the mass solidifies. This lower limit depends upon the composition of the mass, and upon the character of the subsequent processing. In the foregoing examples the soaps would not ordinarily be cooled below about 120 F. to F. because at lower temperatures they become increasingly stiff and resistant to flow.

Thus the extreme temperature range for the agitating step of my process may be defined as to its upper limit as the critical temperature of the soap mass, above which beta soap is not formed by agitating action, and as to its lower ing from the chilling and agitating device is I form-retaining even in relatively large masses. and is thus unsuitable for spreading out on the surface of the chilling roll under the influence of gravity. In the lower portion of the extreme temperature range the agitated soap is, strangely, much softer in consistency and, because in this portion of the range the mass is form-retaining only when in relatively small masses, it readily spreads out and flows over the surface of the chilling roll when the feed hopper is kept well filled to a substantial depth. I have also found that this temperature range of most favorable consistency for spreading on the roll approximately coincides with the temperature range in which the highest proportion of beta phase may be formed by agitating action, and also with the range which produces a product of most loosely knit structure, readily penetrated by water, when the pressure to which the mass is subjected during and subsequent to its agitation does not exceed about 50 pounds per square inch (as is the case in the foregoing examples of my process). Hence my preferred temperature range for terminating the agitation just prior to chilling the soap in ribbon form is novel, is a practical significance from the operating standpoint, and is also of significance in making a very rapidly soluble product due both to a very high beta phase content and to a loosely knit structure.

As an aid in controlling these variables, especially consistency and beta phase content, a thermometer or thermocouple may be installed in the cooling and agitating device to record the temperature of the soap passing from the cooling chamber into drum 42.

I find that generally speaking my process. is applicable to, and my product may be produced from, soap of any composition suitable for detergent soap in flake form which has a real soap formula containing at least about 15 per cent of sodium soaps of saturated fatty acids having at least 16 and not more than 22 carbon atoms per molecule. The essential criterion, as to operable compositions, is the capability of th soap mass to develop the beta phase upon agitation below a critical temperature. I find that sodium soaps of lauric acid and of other saturated fatty acids having a smaller number of carbon atoms than lauric acid, and sodium soaps of oleic acids and of other unsaturated fatty acids which are liquid at ordinary temperatures, when treated by themselves are not transformed into the beta phase under the conditions described herein, although mixtures of' soaps of these fatty acids with sodium soaps of saturated fatty acids containing from about sixteen to about twenty-two carbon atoms per moleculemay, if the mixture contains at least fifteen per cent of such saturated sodium soaps; readily be transformed to the beta phase. When a product containing a very high beta phase content is desired the real soap formula may well contain at least about forty per cent of such saturated sodium soaps.

Sodium soaps made from soap making fats accuse substantially equivalent to tallow, such as palm oil and hydrogenated vegetable and marine oils, may be substituted in whole or in part for tallow in preparing the soap for use in my process. Likewise the soap for my process may contain substantial proportions of sodium soaps of coconut oil or of other tropical nut oils of the coconut oil type such as palm kernel oil, babassu oil, and cohune oil, although satisfactory products have been made by my process without the use of any oils of this type. Soap making fats having characteristics different from those of tallow and coconut oil may also be used; likewise water soluble salts of potash or other basic materials, such as nitrogen bases, may be substituted in part for sodium soaps. By analogy with the operating conditions described for the examples given herein, those skilled in th art will readily recognize suitable operating conditions for any given formula.

My process is applicable in the manufacture of substantially unbuilt soaps in flake form as well as soaps containing varying amount of suitable soap builders. Builders in liquid form (in solution'or as a slurry) may be introduced prior to the step of cooling the soap with sumultaneous agitation, provided the amount of builder thus incorporated is not so excessive in amount as to interfere with the formation of the beta phase. Alternatively, builders may be incorporated immediately after the step of cooling the soap with simultaneous agitation, as in the second of the preceding examples. Suitable builders include sodium silicate, sodium metasilicate, sodium carbonate, trisodium phosphate, sodi'um pyrophosp'hate, sodium perborate, and in general all buildare that are appropriately used in any flake soap product. The soap may be aerated, if desired, prior to the step of cooling with simultaneous agitation.

The most favorable moisture range for the soap when subjected to the cooling and agitating step is from about per cent to about 27 per cent.

The moisture content of the final product of my process may be controlled in accordance with well know practice in making flake soaps of conventional types, although precautions should be taken to avoid heating the soap to a temperature high enough to cause reversion of phase. The moisture content of the product is usually between about 3 per cent and about per cent.

The preparation of powdered and granulated soaps of substantial beta phase content is disclosed and claimed more especially in my copending application, Serial No. 446,757, filed concurrently herewith.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A soap product in flake form, of formula suitable for household and laundry use, containing a substantial proportion of sodium soap in the beta phase, and having a structure typical of a soap which has been whipped mechanically while at a temperature such that the mass is in a condition of pasty cohesiveness and while within the range in which beta soap is formed 'an agitation, and which has been maintained,

both during said whipping and thereafter until formed into ribbons, at pressures sumciently low to avoid substantial compacting of the soap such as would substantially destroy its loosely knit structure, which is readily penetrated and disintegrated by water.

2.). detergent soap in flakeform, having a real soap formula containing at least about ii! teen per cent of sodium soaps of saturated fatty acids having not less than sixteen nor more than twenty-two carbon atoms per molecule, and having a structure and phase composition characteristic of a soap which has been effectively agitated and discharged from said agitating step while above a temperature at which the soap loses its pasty cohesiveness, and within the temperature range in which the beta phase as shown by X- ray diffraction photograph is formed in substantial amount upon agitating, and which has subsequently been cooled substantially to room temperature, said soap in flake form containing a substantial proportion of soap in the beta phase uniformly distributed therethrough.

3. The product of claim 2, in which said soap in flake form comprises as its principal detergent ingredient sodium soaps predominantly in the beta phase.

4. The product of claim 2, in which said soap in flake form comprises as its principal detergent ingredient sodium soaps at least two thirds of which are in the beta phase. 0

5. The product of claim 2, comprising a substantial amount of asoap-builder as well as said soap in the beta phase.

6. The product of claim 2, in which said real soap formula is substantially equivalent to soaps of tallow fatty acids.

7. A soap product in flake form, of formula suitable for household and laundry use, containing a substantial proportion of sodium soap in the beta phase, and having a structure typical of a soap which has been whipped mechanically while within the range in which beta soap is formed on agitation, and while within the more limited range defined as to its upper limit'as the highest temperature (below the critical temperature of the mass) at which the mass will flow under the in-, fluence of gravity and deflned as to its lower limit as the lowest temperature at which the mass possesses a .pasty cohesiveness and is not still and resistant to flow, and which has been maintained, 'both during said whipping and thereafter until formed intoflakes, at pressures sufflciently low to avoid substantial compacting of the soap.

8. In a process for manufacturing detergent soap in flake form containing a substantial amount of soap in the beta phase, the steps which comprise effectively agitating a soap mass while said mass is within a temperature range in which the beta phase of said soap is formed in substantial amount upon agitating and while above that temperature belowwhich said mass loses its pasty cohesiveness, terminating this agitating step while within said temperature range and while above that temperature below which said mass loses its pasty cohesiveness, forming said agitated mass into ribbons, and reducing the moisture content of said ribbons, maintaining said soap comprising soaps predominantly in the beta phase, which comprises the steps or preparing a mass oi. molten soap containing from about ten percent to about twenty-seven per cent moisture, the real soap iormula of which contains at least about fifteen per cent of sodium soaps oi saturated tiatty acids containing not less than sixteen nor more than twenty-two carbon atoms per molecule, cooling said soap mass to a temperature between about 160 F. and 115 F.. within which range beta phase soap is formed on agitation and said mass is in a condition of pasty cohesiveness, effectively agitating said soap while establishing and maintaining same within said temperature range to transform a substantial portion of the soap to the beta phase, forming said cooled and agitated soap into ribbon Iorm and drying said ribbons without rise of temperature above 160 F.

ii. The process described in claim 10, in which;

air is introduced into and dispersed throughout the soap prior to its agitation with cooling.

12. The process described in claim 10, in which a soap builder is introduced in controlled proportion into the soap prior to said ribbon forming 25 flakes.

step.

13. The process of claim 10, in which the real soap formula 01' the mass contains at least about forty per cent of sodium soaps of saturated fatty acids containing not less than sixteen nor more than twenty-two carbon atoms per molecule, and in which the flake soap product contains soap predominantly in the beta phase.

14. In a process of manufacturing detergent soap in flake form containing as its principal detergent ingredient sodium soaps predominantly in the beta phase, the steps which comprise effectively agitating a soap mass while said mass is within a temperature range in which the beta phase of said soap is formed in substantial amount upon agitating, said range being further limited as to its upper limit as the highest temperature (below the critical temperature or the mass) at which the mass will flow under the influence of gravity and as to its lower limit as the lowest temperature at which the mass possesses apasty cohesiveness and is not stiff and resistant to flow; chilling said agitated soap as a thin film and forming same into ribbons; partial- 1y drying said ribbons and breaking same in VICTOR LmiLS.

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