US2295594A - Detergent soap product and process - Google Patents

Description

Sept. 15, 1942. v. MILLS DETERGENT SOAP PRODUCT AND PROCESS Filed Jan. 28, 1941 5 Sheets-Sheet l V. MILLS DETERGENT SOAP PRODUCT AAND PROCESS Sept. 15, 1942.

Filed Jan. 28, 1941 3 Sheets-Sheet 2 Sept. 15, 1942. v..M|LLs 2,295,594 l DETERGENT SOAP PRODUCT AND PROCESS Y Filed Jan. 28, 1941 s sheets-sheet s Patented Sept. 15, 1942 DETERGENT SOAP PRODUCT AND PROCESS Victor Mills, Ivorydale, Ohio, assignor to The Procter and Gamble Company, Ohio, a. corporation of Ohio Ivorydale,

Application January 28, 1941, Serial No. 376,399

20 Claims.

This invention relates to improved detergent soap products and to methods of making the same.

The principal object of my invention is to provide by a relatively simple, economical, and continuous process a solid extruded soap containing a substantial proportion of soap in the readily soluble beta phase, and exhibiting a combination of other desirable characteristics not found in other soaps of similar phase composition. An especial object is to produce soap having a high sudsing rate, in all cases higher than the sudsing rate of ordinary framed soap of identical chemical composition, a quality which makes my new soap especially suited for use in hard water or in cold water.

A feature of the invention is that an aerated soap may be treated, without essential alteration of the steps of the process, in such a manner that it will be given an improved sudsing quality, thus producing a floating soap having al1 the desirable characteristics of my product.

Milled soaps, produced by working solidied but still slightly plastic flakes of reduced moisture content between several successive sets of steel or granite rollers and then compacting the particles in a plodder which extrudes the soap in solid bar form, usually contain (depending upon chemical composition and completeness of milling) a high proportion of a solid soap phase which has been identiiied as the beta soap phase. Framed soaps produced by allowing kettle soap to cool slowly to a solid state may also contain soap in the beta phase but usually in relatively smaller proportion. As will be noted hereinafter, bet-a soap phase is distinguishable by X-ray analysis. Similarly distinguishable is a less readily soluble solid soap phase, referred to as fomega soap, which is formed when soap is rapidly cooled from a molten to a solid state without mechanical working. Of two soap bars of the same chemical composition, moisture content, and general granular structure, that bar which contains the greater ratio of beta phase soap to omega phase soap will develop suds the more rapidly when rubbed during use.

The crux of my invention is the discovery that mechanically agitating or working soap while it is being cooled from a fluid state through various degrees of plasticity causes the formation of beta soap when, and only when, the nal temperature ofthe soapextruding from the agitating operation is reduced below a critical value which varies with the chemical composition of the real soap portion of the mass and with the moisture concases low enough topermit extruding the soap in a form-retaining condition, yet high enough to permit extruding the soap at relatively low pressure in a condition of pasty cohesiveness such that air in nely divided bubble form may be retained when a oating soapis desired. I determine the critical extrusion temperature by noting the value at which the characteristic beta. ring appears in X-ray photographs of soap samples representing different extrusion tempera-l tures. A more readily available means of approximating the critical extrusion temperature is to compare sudsing rates of soap samples representing different extrusion temperatures with the sudsing rate of a sample of kettle soap of the same chemical composition slowly cooled from a rluid to a solid state as in commercial framing practice. The lower temperature limit of my process is readily recognized, when the extrusion temperature is gradually lowered,v as that point below which an aerated soap of any given formula begins to become crumbly and non-cohesive.

One form of apparatus suitable for the practice of the invention, as well as representations of a photographic method of testing the product, is shown in the accompanying drawings, in which Figure 1 is a diagramamtic showing of a preferred form of apparatus for use in the practice of the inst-ant process, including the steps of reducing the moisture content o f ordinary kettle soap while still in a molten condition and then cooling and agitating the same;

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 3-3 of Figure 2;

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

Figures 5, 6, and 'l are representations of photographs of X-ray diiraction patterns of soap in diierent phases. l

In order to facilitate an understanding of the invention and of one method whereby the intion may be practiced, apparatus which may be employed for the purpose is illustrated in th'e 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. A tank II is provided for the storage, of molten soap, the lower portion of this tank.ommunicating through a conduit I2 and a hea'ter I4 with a spray nozzle I6 in a flash chamber I5, a pump I3 being -associated with the conduit I2 to ensure continuous and uniform-flow of soap to the flash chamber. The

heater I4 may be supplied with high-pressure steam or other suitable heating medium, and may conform in structure to any known type of heat exchange device for raising the temperature of liquids. The flash chamber is provided at its upper end with' a vapor pipe Il for the escape of volatilized moisture through a condenser I8, cold Water..or' other condensing medium being supplied to the latter to effect condensation of the discharging vapor,

Following the reduction of moisture content of the soap in flash chamber I5, the molten soap is conveyed through a conduit I9 by a pump to and through a continuous crutcher 46, thence to a cooling device indicated generally at 24. Perfume may be introduced through pipe 41 and thoroughly mixed with the stream of hot soap passing through crutcher 46. Similarly, compressed air or other compatible gas may be introduced, if desired, at this point through a conduit 2I provided with a control valve 22, and distributed throughout the soap. The cooling device 24 is provided with an outlet orifice 25, through which the soap, cooled and otherwise treated as hereinafter described more fully, is extruded in the form of a continuous bar onto a traveling conveyor belt 26. The continuous soap bar may be severed into individual bars or lengths by a cutter, represented schematically at 21, which is disposed above the conveyor 26 and driven in timed relation therewith. In place of this bar cutter any other suitable means for converting the continuous extruded bar into individual bars, for example a bar molding device, may be employed.

The continuousl 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 an aerated molten soap to the cooling device will serve my purpose. Also, while one of the advantages of my process is that it is quick and continuous, the soap may nevertheless be prepared as a batch, either aerated or unaerated, for passage through the cooler and extruder.

Turning now to Figures 2, 3, and 4, constituting sectional views of the cooling 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 Vthe axis of the drum. The drum 29 is formed of heat conducting material, such as metal, and is surrounded by a second cylindrical wall 3I 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 l, 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, inwardly directed arms 36, serving as baffles. A 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 baille arms 36 and cooperating therewith to agitate the soap. From the drum 42, the soap passes through a tapered discharge housing 44 and is extruded from the orifice 25 at the rear thereof. A motor 45 or other suitable driving means may be employed to rotate the shafts 33 and 43, as shown in Figure 1.

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

Sodium soap, in the neat phase, prepared from a mixture of 20 per cent coconut oil and 80 per cent tallow by the usual well known kettle process, and containing about 30 percent of moisture, is stored in tank Il, Figure 1. It is heated to about 390 F., under a gauge pressure of 250 pounds per square inch or more to prevent volatilization of moisture, by pumping through a closed type of heater I4, heated by high pressure steam or other suitable medium. The soap is then discharged through spray nozzle I6 into chamber I 5, where it fiashes 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 to the` boiling point of soap containing this reduced percentage of moisture, or about 223 F.

By suitable adjustment of the conditions of soap temperature before flashing, pressure in the flash chamber, etc., soap of any desired moisture content below that of kettle soap may be obtained while still maintaining fluid condition to permit pumping.

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 sufcient pressure to accomplish this transfer at the rate desired. I have found that a pressure of between about ten and about twenty pounds per the soap in suiliciently square inch, measured near the pump outlet. is usually sulllcient depending on the size of the extrusion orifice and other variables. In the cooling device, while in a thin layer not substantially greater than one inch, the soap is cooled to an average temperature of about 140 F., at

soap in substantial amounts. The relative intensities of the 2.95 A. and 2.75 A. rings, and of other characteristic rings, provide a means oi estimating the relative amounts of these two phases in a sample ,of soap. Thus the proportion of one of these phases in one soap in relation to the proportion ofthe same phase in another soap of like chemical composition can readily be estimated Vby comparison of the intensities of the characteristic ring for .that phase in X-ray diffraction photographs of the two soaps taken under comparable conditions.

The X-ray diiIraction patterns illustrated in 'i the figures were obtained by passing a beam of inner surface of the cooling jacket is quickly scraped ofi' by the scrapers 94 and mixed with uncooled soap, with agitation. In the apparatus described, I flnd a cooling medium consisting of water between 35 F. and 65 F. .to be satisfactory depending on rate of water flow and iinished product properties desired, but cold brine or liquid ammonia or other cooling medium may b'e used instead. The soap then passes through drum I2, where it is further mixed by the rotating arms or X-rays from a copper target through two separated pin holes to eliminate all but substantially parallel rays, passing these rays unfiltered through a one millimeter layer of the soap sample, and recording the resulting radiations on a flat-photographic plate located five centimeters i beyond the sample, the general technique being that described in George L. Clarks Applied X-rays, third (1940) edtion, chapter XIII.

The diameters of the 2.95 A. and 2.75 A. rings on paddles 35 and by passing between the stationary baffle arms 36 without additional chilling. Itis then extruded asa form-retaining mass into the atmosphere or into a low pressure zone through orifice which has the required shape to produce a continuous blank bar of desired form. This continuous bar is cut into short individual bars of the desired length, and these bars are cooled without undue delay to a temperature convenient for the usual final bar stamping or pressing operation, which may suitably be performed when the temperature of the soap is about 100 F. The process is continuous, beginning with soap in storage tank Il up to the bars made by the apparatus described.

Further description of my process and product will be facilitated if consideration is given at this point to important changes that are brought about in soap subjected to my process.

The beta and omega phases, although of identical chemical composition, differ fundamentally in crystalline structure as well as in their different solution and sudsing rates already referred to. The X-ray diffraction patterns exhibited by these two phases are quite diierent and serve to identify them, as illustrated in Figures 5 and 6 for sodium soap made from 20 per cent coconut oil and 80 per cent tallow. For

purposes of identification the presence of the diffraction ring corresponding to an interplanar distance= in the crystal of approximately 2.95 A. as shown in Figure 6 is ordinarily sufiicient to prove the presence of the omega phase, while the presence of the ring corresponding to an interplanar distance of approximately 2.75 A. as shown in Figure 5 is ordinarily suilicient to indicate the presence of the beta phase. The interplanar distances of coursevary somewhat, although usually only slightly, with some variations in the composition of the soap, but the spacings given by way of example, coupled with the diagrams Nos. 5 and 6 illustrating th-e relative intensities of lines and other spacings as well,` will serve to denote the characteristic X-ray patterns of the two phases.

Figure 7 is a representation of a photograph of the X-ray diffraction pattern exhibited by soap containing both beta phase soap and omega phase ythe photographic negatives obtained in this manner were 5.85 centimeters and 6.40 centimeters respectively.

When the 2.75 A. ring is just barely visible on the photograph, after an exposure of minutes with X-rays emanating from a vacuum tube operated `at 40 kilo volts (peak on rectified current) and 25 milliamperes and passing through pin holes having diameters of about 0.025 inch, the soap through which the rays were passed contains a substantial amount of soap in the beta phase. Soap made by my process which exhibits the 2.75 A. ring even faintly is found to have a higher sudsing rate than soaps of the same composition (as regards real soap molecular composition, builder formula, and moisture content) which do not exhibit this ring and which have been made by other processes or by a process similar to mine but above the critical temperature of my process.

The following table shows the comparative sudsing rate: (1) of ordinary framed kettle soap, unaerated, (2) of the same soap dried to 20 per cent moisture before framing, (3) of soap containing 20 per cent moisture made by my new process, (extruded at F.), with the air injection step omitted, (4) the same as 3 but extruded at 204 F. into a small container (because atthis temperature it is not form-retaining) and cooled more rapidly than framed soap, and (5) of ordinary milled soap containing 14 per cent moisture. All of these soaps were soda soaps, made from the same fat formula, namely, 20 per cent coconut oil and 80 per cent tallow. Differences in sudsing rates are measured by determining the number of rubs with a sponge required to produce a stable suds in a gallon of 85 F. water of 7 grains of calcium carbonate hardness per gallon with a bar of a given size and tested under standardized conditions. The number of rubs required for eachof these soaps in this test is due vsolely to the physical condition of the soap. The higher sudsing rates are A comparison of columns 3 and 5 with columns l and 2 shows that soap made by my process 5 and also milled soap are greatly superior to thi framed soaps. high sudsing rate is not obtained when the extrusion temperature in my process is too high.

Same as Sift (Urbe New m Sft framed pgss extr'uglcd milled snap framing at 204 F. soap Moisture content percentVv 30 20 20 20 14 Number of rubs to produce stabli` suds 70 95 48 97 47 When soap at a temperature below its true critical temperature is agitated in such a manner that the particles of the mass are moved with respect to one another, soap which is present in the omega phase is transformed into the beta phase and the sudsing rate of the soap is increased. The extent of this transformation depends upon factors hereinafter mentioned.

Column 4 shows that the desired l may be determined for soap of any formula as hereinbefore described, may also be judged by the appearance, feel, and break of the extruding soap. The following table, for example, indicates typical changes in easily noticeable physical characteristics exhibited by the extruding soap when producing non-aerated toilet soap of to 27 per cent moisture content, when the ex trusion temperature is varied:

Extrusion temperature Depth of color Opacity Firmness Break Well above critical extru- Dark Translucent Semi-fluid. Not form- Viscous fluid.

sion temperature. retaining.

Slightly above critical ex- Very dark ..-.do Very firm. Not fully Like art gum" eraser. trusion temperature. plastic. Breaks by own weirht.

At critical extrusion tem Changing tc dis- C h s n g i n g t o Somewhat firm but pli- Stretches slightly before perature. tinetly lighter. opaque. able. breaking.

Slightly below critical ex- Very light Opaque H Very soft and very pli- Stretches and does not trusion temperature. able. break easily.

The above mentioned true 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 agtation, followed by prompt cooling to room temperature 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 when the aforementioned X-ray diffraction technique is emplayed. Insofar as I have been able to determine, agitation of the soap when above its critical temperature has no effect on the formation of beta soap; whereas when soap is thoroughly agitated below its critical temperature, and then maintained at a stable temperature without further agitation, the resulting amount of beta phase tends to be above the minimum amount required just to exhibit the 2.75 A. ring.

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 26 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 per cent coconut oil soaps and 80 per cent tallow soaps, and it is about 150 F. when the real soap formula is composed of 50 per cent coconut oil soars and 50 per cent tallow soaps. For the latter real soap formula the critical temperature is about 160 F. when the moisture content is 21 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.

In operating the apparatus illustrated, the

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 sudsing 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 formulas, containing about 20 per cent moisture and made by my new process, slowly reverts to omega phase (or reverts to a non-solid phase, and resolidies as omega phase) at temperatures above about F., and reverts more rapidly as the temperature is increased. Soaps of higher moisture content revert somewhat even below 160 F. If heated to temperatures above 200 F. the reversion rate of 2O per cent moisture soap is so rapid that substantially all the beta phase reverts to omega phase or to a non-solid phase within a few minutes. Under these extreme conditions agitating action does not transform soap to the beta phase. Soap made by my process, if extruded at a high temperature at which the beta phase is unstable, must be cooled to a temperature at which the beta phase is stable `before substantial reversion occurs, if a product of the highest obtainable sudsing rate is desired. If, on the other hand, a somewhat lower sudsing rate is desired, the extruded soap may be tempered by maintaining it at a temperature of moderate reversion rate for a controlled period of time so as to obtain a product having a percentage of beta phase intermediate between the minimum substantial amount and the high percentage of beta obtainable by prompt cooling of the extruded soap.

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 satisfactorily cool about 500 to 800 pounds of soap per hour and transform about the same proportion of the soap to the beta or more rapidly soluble phase as the proportion of beta phase soap found in ordinary milled soap of the same real soap formula, when soap of about 20 per cent moisture content, and having a real soap formula consisting of about 20 per cent sodium soaps of coconut oil fatty acids and about 80 per cent sodium soaps of tallow fatty acids, is supplied to the cooling device at a temperature of about 220 F. and is extruded therefrom at a temperature of about 140 F. Under these conditions agitation for as short a period as one minute or even less is effective in producing a suitable amount of transformation to the beta phase. The lower extrusion temperature limit of m process, which as heretofore mentioned is that point below which the extruding soap substantially loses its pasty cohesiveness, apparently due to the solidification of the last remaining nonsolid soap in the mass, is found to be about 125 F. when treating substantially unbuilt soap of the aforementioned real soap formula having any moisture`content between about 14 per cent and 27 per cent. It is somewhat higher for soaps of lower moisture content and is somewhat lower for unbuilt soap of higher moisture content. I use the term pasty cohesiveness to describe that property of soap, at the point of extrusion within my operating range, which enables freshly separated masses of said soap to become reunited when brought together without requiring the application of high pressures such as are employed in plodding milled soap. The extruding soap mass, within the limits of my process, may be considered as a thick pasty magma consisting of a mixture of solid soap crystals in a viscous matrix of unsolidifled soap.

Changes in the extrusion temperature between the critical extrusion temperature and the lower extrusion temperature limit cause changes in the proportions of beta soap, in the sudsing rate, and in the firmness of the resulting product. In general, for soap of any given composition, lower extrusion temperatures within these extremes result in a higher percentage of beta phase soap, and hence ina more rapidly soluble soap; lower extrusion temperatures also result in a softer product. In this respect soap made by my process differs greatly from soap made by the milling and plodding process, for milled soap that has been passed many times through milling rolls and as a result has a very high beta soap content is, firmer than less thoroughly milled soap having a somewhat lower beta soap content.

In making a floating bar soap I prefer to employ extrusion temperatures below those at which the vesiculated air has a tendency to, break through the surface of the soap after extrusion, causing an undesirably rough surface.

The amount of transformation to beta phase which occurs in my process under any given set of conditions with a soap of a given real soap formula may in general be increased (up to the maximum attainable under existing conditions for the particular soap being processed) by any of the following changes in conditions within the limits disclosed: lowering the extrusion temperature; lowering the moisture content of the soap supplied to the cooling device; increasing the amount of agitation per pound of soap produced; lowering the temperature of or increasing the rate of supply of the cooling medium. Thus the beta content of soap produced by this process and the characteristics of the product which depend upon its beta content may be controlled as desired.

The amount of superatmospheric pressure to which the soap is subjected in cooling and agitating device 24 is not critical, the chief require- .v

ment being to supply sufficient pressure to force the soap into and through this device at the desired through-put rate. The pressure required to do this varies with the design and operation of the device and the nature of the soap.

The injection of air or other compatible gas into soap in my process and its fineV dispersionv related characteristics, such as free lathering' quality, are not affected to a significant degree by aeration of the soap.

A suitable amount of air or othergas to introduce into the soap before it enters the cooling apparatus to produce a floating soap is that amount which will produce a Warm extruded bar (at cutter 21) containing about 22 per cent of air by volume, which is equivalent to about 14 per cent by volume when the soap is cooled to room temperature and stamped or pressed into final. bar shape.

If an aerated but non-floating product is desired, sufficient air to produce a bar at cutter 21 containing about 4 per cent or less of air or other gas may be incorporated. This is a sufficient amount to lighten the color of the product appreciably.

Perfume, preservative, -coloring matter, or the like may if desired be incorporated in soap made by my process. When using the apparatus illustrated, any of these materials may .be introduced into the soap in the continuous `crutcher represented at 46 in Figure 1.

I find that, generally speaking, my process is applicable to, and that my product may be produced from, soap of any composition suitable for toilet, household, and laundry purposes, 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. 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 acid 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 16 to 22 carbon atoms per molecule may, if the mixturecontains at least 15 per cent of coconut oil other tropical nut oils having similar characteristics may be substituted, and in place of tallow other fats and hydrogenated oils having similar soap making characteristics may be substituted. Soap making fats having characteristics different from those of tallow and coconut oil may also be used; likewise, watersoluble soaps of basic materials other than sodium may be substituted in part for sodium soaps. By analogy with the operating conditions described for the examples already given, those skilled in the art will readily recognize suitable operating conditions for any given formula.

In making substantially unbuilt soaps, that is soaps containing no more than about one per cent of soap builders, I find that with real soap formulas commonly used in making bar soaps for toilet and general household use the moisture content of the product is preferably no higher than about 27 per cent because such soap which contains over 27 per cent moisture tends to be so soft when extruded at preferred temperatures that it is difficult to handle without marring the bar surface. By employing sodium soaps of fatty acids of high titer I have, however, produced satisfactory bars having an improved sudsing rate with moisture contents as high as 32 per cent. I prefer a moisture content at least as high as ten per cent, because soap containing less than ten per cent moisture tends to be difficult to process because of its relative stiffness. When the moisture content of the soap is within the range ten per cent to thirty-two per cent but is close to either of these extremes, "some adjustment in the composition of the real soap formula may be desirable to offset the resulting firmness or softness of the product.

My process is not limited to substantially unbuilt soaps such as are commonly employed for use in toilet and bath. It may be applied to soaps containing substantial amounts of builders, such as are suitable in soaps for general household and laundry use in the form of bars, flakes, or granules. For example, I have produced a bar soap having improved sudsing rate and containing a substantially increased beta soap content, by subjecting to my process a soap made by thoroughly mixing 75 parts by weight of kettle soap (made by saponifying a mixture consisting of 20 per cent coconut oil and 80 per cent tallow with caustic soda solution) with 24 parts of an aqueous sodium silicate solution (having a density of 40.8 B. at 60 F., and having a ratio of SiOz/NazO of 3.20) and 1 part of aqueous sodium hydroxide solution (having a density of 34.0 B. at 60 F.), and flash drying this mixture to a moisture content of 33 per cent. This soap was extruded from the cooling and agitating device at a temperature of 140 F. Likewise my process has been employed to increase the solution rates of laundry soaps containing soda ash and trisodium phosphate as builders. Other well known soap builders such aslsodium perborate, sodium metasilicate, and sodium pyrophosphate may be employed. Inasmuch as the ordinary milling and plodding process is not applicable to soaps containing substantial amounts of alkaline builders my process is the first one known, so far as I am aware, for increasing the beta soap content of such soap products.

The grains or crystals of which my new soap is composed are apparently aligned or oriented substantially in one direction. This is a property which is also possessed by milled soaps but not by framed soaps or by soaps extruded at such high temperatures that they are not formretaining. The orientation of grains is in the direction of extrusion, and it imparts to the side -surfaces of extruded bars (which are the surfaces that are normally rubbed during use) a solution rate about 10 per cent greater than that possessed by the end surfaces which are substantially perpendicular to the direction of extrusion. The orientation or lack of orientation of the particles of a soap lcan be demonstrated by observing a thin section of the soap (the broad surfaces of which are substantially parallel with the direction of extrusion) placed between crossed Nicol prisms, first with the section of soap turned to the position of maximum light extinction, and then with the section of soap turned 45 from its previous position. An increase in the amount of light transmitted as a result of turning the soap 45 from its position of maximum extinction is an indication of orientation of the particles of the specimen.

'I'he processing steps of the usual milling and plodding operation appear to compact groups of minute soap grains into larger units which tend to be optically homogeneous, resulting in increased translucency. Extrusion of soap at low pressure as in my process, for example below about 510 pounds per square inch, does not appreciably compact the grains in this manner but does tend to orient the grains as previously mentioned. When examined microscopically with polarized light, samples of my new soap are found to contain optically homogeneous grains substantially all of which are less than 0.1 millimeter in average diameter, whereas samples oi' ordinary milled soap are found to contain predominantly much larger optically homogeneous grains averaging more than 0.2 millimeter in average diameter.

Mention has previously been made of the fact that my improved soap in its preferred form is more opaque than milled soaps. It is well known that milled soap is relatively translucent and as a result it is customary when making white milled soaps to incorporate a small quantity of a finely divided solid whitening or opacifying agent to render it opaque and thus improve its appearance. The relative opacity of soap may conveniently be measured by cutting a thin section or film of a representative sample of the soap, this film having a thickness of 11; inch, and determining by means of a retlectometer the amount of light reflected under standardized lighting conditions, first when the lm is placed on a perfectly black background, and second when the 111m is placed on a white background. The rst reading multiplied by and divided by the second reading I call the opacity value of the soap. This testing procedure is similar to that employed in determining the opacity of paper, as described in Sutermeisters Chemistry of Pulp and Paper Making, 2nd edition, p. 479. I have found that a typical sample of soap made by my new method as herein described, except that the step of injecting gas was omitted, has an opacity value of 89, when measured on a surface that is substantially parallel with the direction of extrusion of the soap. Soap of the same real soap formula and the same moisture content when made by the milled soap process, except that no opacifying agent was added, this milled soap having substantially the same beta soap content as the aforementioned typical sample of my new soap as shown by their X-ray diraction patterns. is found to have an opacity value of only '10. Unaerated framed soap of the same real soap formula and the same moisture content isfound to have an opacity value of 84.

Under comparable conditions as to bar size, bar temperature, age of bars, etc., my improved soap in its preferred form is found to be softer than ordinary milled soap of the same real soap formula, the extent of the diiference in rmness between the two types of soap depending upon the moisture content and the extrusion temperature of my soap.

The superior sudsing ability of my novel product is due in some measure to its granular structure, in which term are included such` characteristics as grain size, orientation lof grains, relative firmness of the cohesion of grains, and softness of product for a given chemical and phase composition.

The terms ordinary framed soap, ordinary framed kettle soap," and Corresponding framed soap" designate soap made by cooling uid soap from a temperature at which it will readily ilow into the frame, without producing undesirable streaks in the product due to viscous flow, to a temperature at which it is substantially solid, at a rate substantially that of the rate of cooling of the center portion of an ordinary frame," containing about 1000 pounds of soap, cooled by natural convection of air havingv an initial temperature oi about 85 F. Soap such as that sold for many years past under the trade-mark Ivory may be considered as a typical framed kettle soap of the floating variety.

Having thus described the invention, what is claimed as new and desired to be secured by Lettors Patent is:

1. In a process of manufacturing detergent soap containing a substantial amount of soap in the beta phase, the steps which comprisechilling a soap mass, and while chilling said mass, eifecA tively agitating the same and extruding the mass in continuous bar form, said agitating and extrusion being concluded while the soap mass is at a temperature at which the soap is in a condition of pasty cchesiveness, and is within the temperature range in which the beta phase as shown by X-ray diffraction photograph is formed in substantial amount upon agitating, whereby the sudsing rate of the'soap is materially'increased.

2. In the process of manufacturing detergent soap containing a substantial amount of soap in the beta phase, the steps which comprise effectively agitating an aerated soap mass and extruding said mass in continuous bar form while above a temperature at which the soap mass loses its pasty cohesiveness, and within the temperature which the beta phase as shown by X-ray diffraction photograph is formed in substantial amount upon agitating, whereby the sudsing rate of the soap is materially increased, and promptly chilling the extruded bar to an extent suilicient to stabilize the phase composition of the soap.

3. In a process of manufacturing detergent soap containing a substantial amount of soap in the beta phase, the steps which comprise ilash drying to a moisture content of not less than about ten per cent molten neat soap of high temperature, chilling the soap and concurrently and effectively agitating the same and mixing all portions of the mass and extruding the same in continuous bar form, said agitating and extrusion being concluded while the soap mass is at a temperature at which the soap is in a condition ture range in which the beta phase as shown by X-ray diffraction photograph is formed in substantial amount upon agitating, whereby the sudsing rate of the soap is materially increased.

4. In a process of manufacturing detergent soap containing a substantial amount ot soap in the beta phase, the steps which comprise ilash drying to a moisture content of not less than about ten per cent molten neat soap of high temperature. aerating the resulting soap mass, chill-i ing and concurrently and eifectively agitating said mass and mixing all portions of the mass and extruding the mass in continuous bar form, said agitating and extrusion being concluded while the soap mass is at a temperature at which the soap is in a condition vof pastycohesiveness, and is within the temperature range in which the beta phase as shown by X-ray diifraction photograph is formed in substantial amount upon agitating, whereby the sudsing rate of the soap is materially increased.

5. In a process for preparing soap, containing a substantial amount of soap in the beta phase. and of formula suitable for toilet, household, or laundry use, the steps which include effectively agitating a mass of said soap while cooling said soap mass from a temperature at which same is molten to a temperature such that the mass is in a condition of pasty .cohesiveness, and such that at least a substantial proportion of said mass is within the temperature range in which soap may by agitating action be transformed into the beta phase, the extent of agitation being' suflicient to produce a soap product containing a substantial amount of soap in the beta phase, subjecting said agitated soap for a controlled period of time to an elevated temperature at.'

which reversion from beta phase to omega phase occurs at a moderate rate, thereby controlling the sudsing rate of the nshed product, and thenceforth subjecting said soap to temperatures at which soap in the beta phase is stable.

6. In a process for making floating bar soap, containing a. substantial amount of soap in the beta phase, and of formula suitable for toiletand household use, the steps which include incorporating in and distributing lthroughout a mass .of said soap a sufficient volume of a compatible gas to impart to the bar soap product a density less than that of water, effectively agitating said mass, while establishing and maintaining the same at temperatures such that the mass is in a condition of pasty cohesiveness, and such that at least a substantial proportion of said mass is within thev temperature range in which soap may by agitating action be transformed into the beta phase, the extent of agitation being sufficient to produce a soap productl containing a substantial amount of soap in the beta phase, and thenceforth subjecting said soap to temperatures at which the soap of-beta. phase contained therein is stable.

7. A process for preparing a oating bar soap of reduced moisture content and increased sudsing rate as compared with ordinary commercial floating framed kettle soaps and containing a substantial amount oi' soap in the beta phase, which comprises the steps of incorporating and uniformly distributing in minute bubble form a' compatible gas throughout a continuous mass of molten soap containing from about 14 per cent to about 27 per cent moisture, the real soap formula of which contains at least about 15 per of pasty cohesiveness, and is within the temperacent of sodium soaps of saturated fatty acids containing not less than 16 nor more than 22 carbon atoms per molecule, the proportion of said gas being sufilcient to cause the finished product to float in water, cooling said soap mass to a temperature between about 160 F. and about 125 F., within which range beta phase soap as formed on agitation and at which same is in a condition of pasty cohesiveness, effectively agitating said soap while establishing and maintaining the same within said temperature range to transform a substantial portion of the soap to the beta phase, forming the resulting product into bars, and thenceforth subjecting said bars to temperatures below those at which reversion of beta Phase t omega phase takes place.

8. A continuous process for preparing afloating bar soap, containing a substantial amount of soap in the 'beta phase, and suitable for toilet and household use, this soap Ibeing characterized by its increased sudsing rate as compared with floating .framed soap of like formula and moisture content, which comprises the steps of continuously incorporating compatible gas, in amount sumcient to impart buoyancy in water to the nished soap product, into a flowing mass of soap containing from about 14 per cent to about 27 per cent moisture and having a real soap formula including at least 15 per cent of sodium soaps of saturated fatty acids having not less than 16 nor more than 22 carbon atoms per molecule;

continuously cooling said flowing mass from amolten condition above about 160 F. to a formretaining condition of pasty cohesiveness between about 160 F. and about 125 F., within which range beta phase soap is formed on agitation; effectively agitating said mass both during' said cooling step and immediately subsequent thereto in a manner adapted to transform a substantial portion of said soap to a more rapidly soluble form; extruding said cooled and agitated mass in uninterrupted blank bar form; and cutting said uninterrupted bar into individual bars.

9. A process for preparing a new type of floating bar soap, containing a substantial amount of soap in the beta phase, and suitable for toilet and household use, characterized by an increased sudsing rate asV compared with ordinary commercial floating framed kettle soaps, which comprises the steps of continuously passing into a confined space molten soap, throughout which has been distributed in small bubble form a compatible gas in amount sufficient to impart buoyancy in water to the finished soap product, said soap containing from about per cent to about 32 per cent moisture and having a real soap formula which contains at least about per cent of sodium soaps of saturated fatty acids having not less than 16 nor more than 22 carbon atoms per molecule, continuously advancing said soap through said confined space and simultaneously cooling same in thin films from said molten condition to an average temperature between about 160 F. and about 125 F., within which range beta phase soap is formed on agitation, eifectively agitating said soap both during said cooling step and immediately subsequent thereto while in said confined space to form a well mixed soap magma containing vesiculated gas distributed therethrough and to transform a substantial portion of said soap to a more rapidly soluble fonn, continuously extruding said soap from said confined space in blank bar form while in a condition of pasty cohesiveness, and thenceforth subjecting said extruded bar soap to temperatures below those at which reversion of the more rapidly soluble form to the less rapidly soluble form occurs.

10. A process for preparing floating bar soap, containing a substantial amount of soap in the beta phase, and suitable for toilet and household use which comprises the steps of continuously passing molten soap into a confined space, said soap containing about 20 per cent to 27 per cent moisture, said soap having a real soap formula consisting of about 75 per cent to 85 per cent sodium soaps of fatty acids of the tallow type and about 25 per cent to 15 per cent sodium soaps of fatty acids of the coconut oil type, and said soap having incorporated and distributed throughout same an amount of air sufficient to reduce the specific gravity of the soap to about 0.75 to 0.85, measured soon after extrusion from said conned space; continuously advancing said soap through said confined space and simultaneously cooling same from said molten condition to a partially solidified condition at a temperature between about F. and 140 F., within which range beta phase soap is formed on agitation; effectively agitating said soap both during said cooling step and immediately subsequent thereto while in said confined space; and continuously extruding said soap from said confined space in blank bar form.

11. A detergent bar soap having a real soap formula containing atleast about 15 per cent of sodium soaps of saturated fatty acids having not less than 16 nor more than 22 carbon atoms per molecule, and having the granular structure and phase composition characteristic of a soap which has been effectively agitated and extruded 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 cooled substantially to room temperature without further agitation, said bar soap containing a substantial proportion of soap in the beta phase uniformly distributed therethrough.

12. A detergent soap containing a substantial amount of soap in the beta phase and having a real soap formula containing at least about 15 per cent of sodium soaps of saturated fatty acids having not less than 16 nor more than 22 carbon atoms per molecule, having a phase composition of the character that results from effectively agitating a mass of said soap while cooling same from a molten condition to a form-retaining condition of pasty cohesiveness below its critical temperature, and having a granular structure of the character that results from extruding said4 cooled agitated mass at a pressure insufilcient to compact the grains thereof into substantially larger optically homogeneous units.

13. In a process of manufacturing detergent soap 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 below which said mass loses its pasty cohesiveness, and extruding said mass in continuous bar form while within said temperature range and while above that temperature below which said mass loses its pasty cohesiveness.

14. In a process of manufacturing detergent soap containing a substantial amount of soap in the beta phase. the steps which comprise eectively agitating an aerated soap mass while said mass is within a temperature range in which the beta phase of said 4soap is formed in substantial amount uponagitating and while above that temperature below which said mass loses its pasty 5 cohesiveness. and extruding said mass in continuous bar form while within said temperature range and while above that temperature below which said mass loses its pasty cohesiveness.

15. A detergent bar soap having a real soap formula containing at least about percent of sodium soaps of saturated fatty acids having not less than 16 nor more than 22 carbon atoms per molecule, and having the granular structure and phase composition characteristic of a soap which 15 has been effectively agitated and extruded 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 20 amount upon agitating, and which has cooled substantially to room temperature without further agitation, said bar soap containing a substantial proportion of soap in the beta phase uniformly distributed therethrough and containing a compatible gas substantially uniformlydistributed therethrough in minute vesicular form.

16. A soap of formula suitable for toilethouse hold and laundry use, containing a substantial proportion of sodium soap in the beta phase, and having the granular 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 on agitation, and which has been maintained, both during said whipping and thereafter until fully solidified, at pressures sufilciently low to avoid substantial compacting of soap grains such as would substantially increase the translucency and firmness of said soap.

17. A floating bar soap suitable for toilet and household use containing a ne dispersion of vesicles of a compatible gas in suilicient quantity to reduce the density of said soap below that of water, said soap containing from about ten per cent to about twenty-seven per cent of moisture, having a real soap formula including at least fifteen per cent of sodium soaps of saturated fatty acids having not less than sixteen nor more than twenty-two carbon atoms per molecule, containing a substantial proportion of sodium soap in the beta phase, and having the granular structure typical of a soap of said composition which has been cooled from a molten condition above about 160 F. to a form-retaining condition of pasty cohesiveness, in which condition said soap is a mixture of soap in solid phase and soap in non-solid phase, between about 160 60 F. and about 125 F., within which range beta phase soap is formed on agitation, and which while being so cooled and immediately subsequent thereto has been eifectively agitated. and which has subsequently been extruded while still in said condition of pasty cohesiveness.

18. A floating bar soap suitable for toilet and household use, containing a fine dispersion of vesicles of a compatible gas in suillcient quantity to reduce the density of said soap below that of water. said soap containing from about ten per cent to about twenty-seven per cent of moisture, having a real soap formula composed of about .seventy per cent to ninety per cent sodium soaps of fatty acids of the tallow type and about thirty per cent to ten per cent sodium soaps of fatty acids of the coconut oil type, containing a substantial proportion of soaps in the beta phase, and having the granular structure typical of a soap of said composition which has been cooled from a molten condition above about A 160 F. to a form-retaining condition of pasty cohesiveness. in which condition said soap is a mixture of soap in solid phase and soap in nonsolid phase, between about 160 F. and about F., within which range beta phase soap is formed on agitation, and which while being so cooled and immediately subsequent thereto has been effectively agitated, and which has subsequently been extruded while still in said condition of pasty cohesiveness.

19. A detergent bar soap having a real soap formula containing at least aboutA l5 per cent of sodium soaps of saturated fatty acids having not less than 16 nor more than 22 carbon atoms per molecule. and having the grammar structure and phase composition characteristic of a soap which has been effectivelyl agitated and extruded 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 cooled substantially to room temperature without further agitation, said bar soap containing a substantial proportion of soap in the beta phase. uniformly distributed therethrough and containing a substantial amount of a soap builder.

20. A detergent bar soap having a real soap formula containing at least about l5 per cent of sodium soaps of saturated fatty acids having not less than 16 nor more than 22 carbon atoms per molecule, and having the granular structure and phase composition characteristic of a soaD which has been eiectively agitated and extruded 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 dilfraction photograph is formed in substantial amount upon agitating, and which has cooled substantially to room temperature without further agitation, said bail soap containing a substantial proportion of soap in the beta phase uniformly distributed therethrough, containing a substantial amount of a soap builder, and containing a compatible gas substantially uniformly distributed therethrough in minute vesicular form.

VICTOR MILLS.

CERTIFICATE OF CRRECTION.`

Patent No. 2,295,54..

September l5, VICTOR HILLS.

It is .hereby certified that error Vappears in thevprinted specification of the above numbered'patent requiring correction as follows: Page 1, second column, line 55, for "zagramamtic" read diagrmxmxatic; line jl-52, for "intlon" read invention-fg page 6, second column, line 28, for 510 pounds" read --50 pounds; fore *which* lnsertf--range 1n; and that the said Letters Patent should be read 'with this correction therein that the same may conformto the rec- Qrd of the eeeef 1n' the Petent office.

signed and sealed une auth dey ef November, A. D, 19m.

Henry Van Ar'sdale (Seal) cting Commissioner of Patents.

page T, first column, line 58,4c1a1m 2, be'

- CERTIFICATE oF CORRECTION.' Patent No. 2,295,594.

September l5, l`1.2.

VICTOR HILLS.

It is.hereby certified that error lappears in thelprinjted specification of the above nmnbered'patent requiring correction as follows: .Page l, second column, line 55, for Wlagznamaxnticl read --diagramnatic--g' line jl-52, for *intion* read --invention.; page 6, second column, line 28, for "510 pounds" 'read --50 pounds; fore which insertj--range 1n; and that the said Letters Patent should be read 'with this correction therein that the same may confrmto thel rec- Qrtd of the case'- 1n' the Ptent office.

signed ma sealed this 21mm day of November, A. D, 19m.

Henry Van Ar'sdale,

(Seal) cting Commissioner of Patents.

page Y, first column, line 58,4 claim 2, be'

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