US2686761A - Detergent product having milled soap properties - Google Patents

Description

Aug 17, 1954 R. H. FERGUSON ErAL 2,686,761

DETERGENT PRODUCT HAVING MILLED SOAP PROPERTIES Filed June 2, 1950 2 .3 R 6 E 2 m 4 w n ,M n m m. 9 8 6 5 4 3 2 ...n ...om @2N 70M R n M n n 4 am .A 1. m 8 7 6 5 4 3 2 N F Sz Il. t n l PU MNa 65 P R Win. 44 and H5 Y As n ma a 0I MN VI LM, n MV MB WATER Ea. 5.

ATTQ RN EYS UNITED STATES PATENT OFFICE DETERGENT PRODUCT HAVING MILLE SOAP PROPERTIES Ralph H. Ferguson, Springlield, and Francis B. Rosevear, Cincinnati, Ohio, assignors to The Procter & Gamble Company, Cincinnati, Ohio,

` a corporation of Ohio Application June 2, 1950, Serial No. 165,708

19 Claims.

This invention relates to soap products which have high water and salt contents and yet have milled soap characteristics, and to a method of making them.

Milled soaps possess easily recognized characteristics which distinguish them from other commercial types of soap and which make them desirable for many purposes. Among these characteristics are a uniform texture, rm consistency, a smooth, waXy feel, surface glossiness, grain or crystal orientation substantially in one direction, translucency (when opaque whitening agent is omitted), freedom from warping or distorting as the bars age and dry out, tendency to swell when soaked in Water and yet to return to substantially the original shape and appearance after drying, rapid rate of solution in water, especially when rubbed, and consequent profuse lathering power. Other characteristics, to be discussed hereinafter, are the presence of soap inlthe beta crystal phase, and the lowering of the thaw point of the liquid in the bar.

Milled soaps are conventionally made by milling a low moisture, low electrolyte soap (e. g. -15% Water and Ofi-0.6% salt), that is by passing the largely solidified but still plastic soap between a series of rotating rolls, succes-y sive members of the series rotating at higher speeds and at closer clearances, the soap being thus subjected to mechanical working, shearing and compacting. The emerging sheets or ribbons of soap are then further mechanically Worked, with shearing and compacting, by being forced through one or more orices or" restricted size by the pressure of an Archimedean screw revolving within a closed barrel. The action of the screw in compressing the soap and forcing it through the orifice is known as plodding and extruding. The mechanical working results in a rise in temperature, which may be regulated by adding or abstracting heat as desired. The combined effect of temperature and of extrusion under pressure is to weld the soaptogether and cause it to emerge from the orifice as a homegeneous, coherent, slightly plastic bar, which is then cut into suitable lengths and stamped for use.

Heretoiore, milled soaps have been made only from soaps which are low in Water and in electrolyte content. The neat soap of the kettle, i. e. the so-called kettle soap obtained according to conventional soap-boiling practice by Settling over nigre, contains about 0.4% or more of sodium chloride and up to about 0,1% of sodium hydroxide or NazCOa, but for milling purposes it is excessively high in water, normally running about S30-32% H2O. Milling of such soap has been unsatisfactory because of the stickiness of the flakes, the softness of the extruded bars and their lack of the desirable milled soap characteristics. A drying process is therefore commonly practiced before milling, whereby the water content is reduced to about 10% to 15%, but this of course adds to the eX- pense of the soap manufacture.

It is an object of this invention to provide a milled type of soap of high moisture'content and a process for making same. It is a further object to prepare such milled type soap from soap originally of high moisture content without incurring an expensive drying step. lt is a further objectto preparesoap flakes and bars of high moisture and electrolyte content yet possessing milled soap characteristics. It is a further object tol provide built soaps possessing the properties of milled soaps. Other objects will become apparent in the description which follows.

We have found that the above and other objects can be attained by mechanically working and compacting (i. e. by subjecting to shearing forces under pressure) a plastic solid mixture of soap, water and electrolyte, the relative proportions of the constituents and the temperature being controlled in such manner, as hereinafter described, as to yield a product of the desired properties. Generally speaking, the soap of our invention may be characterized as a novel milled soap composition which differs from previously known milled soap in a materially increased content of both water and salt or other suitable electrolyte. Our invention opens up a broad new range of compositions for the production of soap products having very desirable characteristics. i

The attached drawings are Figs. 1 to 5, in which graphs are given showing the proportions of water and of electrolyte present in the detergents of our invention, the electrolyte in Fig. 1 being sodium chloride, that iniFig. 2 being tetrasodium pyrophosphate, that in Fig. 3 being pentasodium tripolyphosphate, that in Figui being trisodium orthophosphate, and that in Fig. 5 being sodium silicate. l

We shall first describe our invention as if it were restricted toy a ternary mixture of soap, water and electrolyte in which the soap is the sodium soap of a lmixture of tallow and 20% coconut oil, and in which the electrolyte 3 is sodium chloride. Later we shall outline our invention more broadly.

The soap for our process can be made by the familiar boiled process in the kettle, with purification by settling and separating'into immiscible phases, or by the semi-boiled or cold processes, well known to those skilled in the art, or by continuous saponilication of fatty acids under pressure as described in U. S. 2,159,397, or by any other method desired. The soap can be adjusted to the desired water content by any suitable means, or it can if desired be used without adjustment of Water content ii in the manufacture of the soap a suitable water content is attained. lf any water is to be removed, obvious means may be employed, such as'partial drying of llakes in a drying chamber or spraying the molten soap at high temperature and pressure into an evaporation chamber at lower pressure whereby water is vaporized, conditions being so controlled as to give the desired Water content. Alternatively, partially-dried soap can be mixed in suitable proportion in acrutcher with molten undried soap until uniform and homogeneous and of the desired water content. If, on the other hand, the water content of the original soap is too low, this can 4be remedied by crutching a water solution of electrolyte, such for example as sodium silicate, into the molten soap before cooling and solidifying same. Electrolyte can be added to the soap as required, either in dry form or in solution; `we preferably, but not necessarily, mix it with the molten soap in a crutcher.

TREATMENT IN THE PLASTIC' SOLID STATE As hereinbefore stated, our process involves mechanical treatment of a soap-salt-water system which is in a plastic'solid condition, deformable under pressure but substantially incapable of ow under the action of .gravity alone or of welding together on contact after severance unless eonsiderable pressure is applied. The desired state of plasticity can be attained by-any suitable means, such for example as by cooling to flake or ribbon form in a thin lm over a cooling roll, or by cooling .with agitation as for example in a continuous cooling device (e. g. a Votator) such as that described in U. S. 2,295,596, in which case the-soap is conveniently extruded as ribbons, sheets, threads or cylinders of small diameter, depending upon the size and shape of the orifice or orifices. Furthermore, it is not in all cases necessary that the soap-salt- Water system be homogeneous at the beginning' of the mechanical treatment, since by such treatment a heterogeneous system can inmany cases be made homogeneous. yThe following discussion will aid in understanding the plastic solid condition contemplated in our invention.

It has been proposed in the past that bars of soap 'as normally encountered in the household are completely solid, the water content thereof entering into the crystal structure in the manner of water of hydration. More recent research leads us to believe instead that at ordinary temperatures of use, vbars of soap, unless extremely dry, are commonly composed of solid soap crystals enmeshing a small amount of a dilute liquid solution of soap in v/ater, known as nigre, and that only when chilled to some temperature below C. does this'liquid freeze to ice and the bar becomes wholly solid. At temperatures which are rsuiliciently low, even though /they may be above the melting point of the ice,

soap of moderate viscosity or middle soap of high viscosity. As the temperature of this two-phase, solid-liquid system rises still further, more and more solid crystals are converted into fluid and eventually the solid phase disappears entirely.

We are not concerned with a wholly fluid system, nor do we practice our invention at temperatures at which the soap is of a pasty consistency such as characterizes a mixture composed substantially of soap crystals and neat soap, as in Mills U. S. Patent 2,295,594, or at a temperature such that the soap is suiiiciently soft to be extruded at low pressure, ras lor-example atabout 5 to 25 lbs. perfsquarev inch asin Ittners U. S. Patent 2,377,424. ln such 'systems the fluidity is too great to permit .applying the requisite shearing forces, and the resultingsoaps, which are free from the shear stresses and' internal cleavage planes which are characteristic results of `milling, ploddingand extruding ysoaps in the plastic solid condition, are also lacking in important milled soap characteristics. In order to produce these properties in our high moisture, highfsalt compositions, they must besubjectedto shearing forces resulting from differential movement in the plastic solid state under high pressure, such as the pressures exerted by milling rolls, orfplodding and-extrusiony pressures ofthe order of about lbs. or more per square inch. We prefer to operate at a temperature at which our soap-water-electrolyte system is composed of a large proportion of soap crystals and a small proportion of dilute nigre,since in ysuch systems milled soap properties can be attained most easily and to the highest degree. However, in Isome systems containing a large proportion of crystals and a low proportion of middle soap, the viscosity or plasticity is such as to permit setting up the shearingforces and pressures of our invention and the production of milled soap properties thereby. In general, therefore, We practice our process at temperatures at which neat soap cannot exist in stable equilibrium, i. e. at temperatures below the solidiiication temperature of the system but above the temperature at which it becomes brittle, and such that the system is in .a plastic solid condition composed essentiallyof a mixture of a large proportion of solid soap crystals with a small proportion of a fluid soap phase which is stable at such temperatures and which may be either nigre or middle soap.

The minimum temperature at-which neat soap can stably exist can be determined for a given soap composition in apluralityof ways, one AWay being the Well known dilatometric method, since simultaneous appearance vor disappearance of neat soap is accompanied by a change in slope in the volume-temperature curve of the system.

Satisfactory mechanical working and compacting of the soap for the purpose of our invention can take place only when it is substantially inthe plastic solid condition as described above. Our process comprises subjecting it, in this condition, to a mechanical kneading, shearing andcompacting treatment, such for rexample as it receives when passing between conventional milling rolls,

but any other means of giving it such treatment can be employed. The action of the milling rolls can be supplemented by the compacting and working action of plodding and extruding. In fact, oft-repeated high pressure extrusions through small orices accomplish a mechanical working, shearing and compacting similar in nature and in effect to passage through a series of millings rolls, due to the linear flow of the soap under pressure, presumably with adjacent layers flowing at different relative speeds. It will be understood, therefore, that our process is capable of producing soap of milled characteristics in ake form by passage over and between milling rolls or by repeated extrusion through a narrow slit, or in bar form by milling, plodding and extruding, or in other forms such as threads or spaghetti-like noodles depending upon the size and shape of the extrusion orifice.

CRYSTAL PHASE-S IN SOAP For an adequate understanding of the results produced by the mechanical working and compacting of our invention, a brief discussion of phase relationships in soaps is required. Solid commercial soap is known to exist in at least three distinct crystalline phases, designated beta, delta and omega, which are convertible into one another. These phases appear either in the finished product or at some stage in the manufacturing process, sometimes existing alone, sometimes in mixtures with one another. Gen-n eralizing broadly, it may be said that beta phase is favored by mechanical working of relatively low moisture soaps of usual formulae at suitable temperature, that omega is favored by quietly cooling such soaps from a molten condition in the absence of agitation, and that delta is favored by high molecular Weight, and by high Water content and low temperatures, as for example when soap nigres solidify.

Differences in crystalline structure are reflected in differences in phsyical properties for the phases. (Ind. Eng. Chem., 35, 1005 (1943)) give data illustrating this for three samples of the same soap, each sample having been processed differently in order to yield a dierent crystal phase. Their data show soap which is in the beta phase as a result of milling and plodding, to be much firmer and more readily soluble, and to lather more easily, than either of the above mentioned phases, and to be distinguished by its greater tendency to swell when soaked in water. Their milling and plodding produce the beta phase under conditions tending toorient and press the crystals together. If the conditions of producing the beta phase are such that the crystals are not packed, joined coherently, or oriented in parallel fashion (as for example by chilling and mechanically working the semimolten soap While in a state of pasty consistency) the ease of lather is retained, but optical discontinuities occur, translucency and the characteristic waxy milled characteristics are lost, and the bar tends to disintegrate in water and to be in general much softer.

The various crystalline phases of soap can be distinguished from one another and identified by certain characteristic X-ray diffraction rings which for a given phase remain practically unchanged by variations in fat formula, water content or electrolyte content, although such variations may be determinative of the phase which forms. A simple system of identification is based upon the characteristic short spacings shown in Ferguson, Rosevear and Stillman Table I, taken from the paper by Ferguson, Rosevear and Stillman referred to above.

Table I IDENTIFYING X-RAY DIFFRAGTION RINGS Ring Diameter Lattice Spacing Om. d./n., A.

2.75. 2.85 and 3.55.

NOTE-The identifying rings for alpha phase have been omitted because of failure thus far to discover this phase in any commercial soap.

Not only is the presence or absenceof a phase shown by the presence or absence of its identifying ring or rings; the relative proportions of the soap present in two or more phases which coexist, can be estimated for an unknown sample from the relative intensity of the identifying rings; for example, if the omega phase is progressively converted into the beta phase, the relative intensity of the 5.85 cm. ring decreases and the relative intensity of the 6.35 cm. ring increases as the conversion proceeds. In order to make such estimates with a degree of precision, known mixtuers of the phases, each in as pure form as possible, are first made up as standards and the relative intensities of the characteristic rings are noted. The relative intensities of the rings in the diffraction pattern of the unknown sample are then compared with these standards. By way of example, a mixture of beta and omega phases which gives approximately equal intensities of the 6.35 cm. and 5.85 cm. rings will actually contain about beta and 25 omega phase. A soap which ispredominantly beta, but which contains less than about 5% omega will clearly exhibit the beta ring, but the omega ring will be scarcely perceptible. On the other hand, in order to obtain detectable beta rings in a soap which is predominantly omega, as much as 15% or 20% beta soap may have to be added thereto.

Progressive conversion of one phase into another results in progressive change in certain physical properties, as illustrated in Table II. Here soap-boilers neat soap of the kettle was made from tallow and 20% coconut oil. It was flash-dried to 15% water, the resulting particles being in the omega phase. The effect of progressive conversion to beta phase by increasing amounts of working and compacting was determined by subjecting identical portions of the above soap to different numbers of extrusions through a slit orice at room temperature and under pressure such as to form bars. The iirmness of the bars, or their breaking strength, was determined with a Mullen Tester (an instrument widely used by paper manufacturers to test the strength of their product), and the rate of wear of the bars was determined by mechanical treatment with a rotary brush under a stream of water.

Table II PhasnCginpost-on Rvte of y -ray ear No. of Times (Rotary Extruded Brush) (lbs /in 2) Percent Percent (Arbitrary eta omega Units) f gloss, translucency,

Although the'mechanical working and pres; sure treatment,offourfprocess convertsthe highmoisture, high-electrolyte soaps of our invention predominantly into the beta phase, and although existencev of such soaps predominantly in this phase is essential to possession by them of milled soap properties in characterizing degree, yet it is notv to be understood-'that mechanical Working of any soapfnecessarily converts it into the beta phase; for example a soap containing' only 6%-7.% water and existing predominantly in the beta phase has under suitable extrusion conditions been converted into the omega phase, with resulting decrease in firmness, rate of wear, lathering power, etc., and at'high moisture, in the absence of addedlelectrolyte, a framed bar in the beta phase can be converted by extrusion or plodding into a soft delta bar.- Furthermore, mechanical' working of omega does not per` se. markedly increase lather; it is when such working effects conversion to beta that improvement results, and this is dependent both upon the composition ofthe soap and'upon the temperature, duration and degree of working and compacting.

BASIS FOR CLASSIFYNG`OUR SOAP AS A MILLED SOAP As pointed out above, the presence of a proportion of soap in the beta phase is indispensible to the possession of milled soap properties. Although in some cases commercial milled soaps of the past have contained less than 50% of the betaphase, presumably due to incomplete milling, yet in order to have milled properties vto the degree contemplated herein, and such that the' product can be unequivocally recognized as a milled soap, about 50%- or more of the soap in our product must be in the beta phase. I-Iowever, rthe typical firmness, translucency, glossiness, waXiness, reversible swelling in water, etc. of milled soap may be lacking even in soap which is predominantly beta phase. For example, soap made by the Mills process according to U. S. 2,295,594 .is largely beta, but it is lacking in these milled soap characteristics, despite its high lathering power and its high beta content. In that process, molten soap of "suitable composition is rapidly chilled and agitated while in a lstate of pasty cohesiveness. The product of that process is softer and more opaque than a milled soap.

With respect to milled soap characteristics, it is in some cases hard to compare our products quantitatively'with soaps of the same composition obtained by other processes because it is in some cases impossible to make coherent, homogeneous bars of high moisture and high salt content by any other process. In certain other high moisture, high salt compositions, coherent, homogeneous bars can be formed by other processes (as for example by framing or by the method of Ittners U. S. Patent 2,377,424), but these bars are lacking in the milled soap characteristics of rmness and reversible swelling in water. In the case of the high moisture, high salt compositions which are susceptible to preparation in bar form bymethods other than ours, direct comparison of bars so formed withour bars with respect to gloss, translucency, rmness, and reversible swelling in Water will show the effectiveness of our shearing and pressure treatment in producing milled soap characteristics.

In determining translucency, the method described in Mills Patent 2,295,594 is satisfactory, opacity rather-than..translucencybeing measured ground and (b) whenl it is placed on a white background. The first reading multiplied byv 100` and divided by the second reading we call theopacity value ofr the soap, this being the recip-v rocal of the translucency. In the example given inthe Mills patent', the product-of that processl hadv an opacity value'ofy 89 as compared with-70f for the same soap whenv it' was milled', despitefthe fact that X-ray diffraction patterns showed' both soaps to be of the same beta content'.

Opacities as lowas 27 have been obtained in" practicing our invention, the values normally.' running between this general range and the range of about 70 given by Mills for a milled low moisture, low electrolyte soap.

The rmness of bars can readily be measured with a Mullen tester. Table III shows illustrative opacity and firmness data on two samples" of the same soap tallow, 20% coconut oil), one sample being framed (i. e. allowed to solidify by slow cooling from the molten state without' agitation) the other being extruded until it possessed marked milledsoap properties.

Table III Framed Extruded Percent NaCl 3. 2 same Percent H2O 27. 2 25. 6l Firmness (Mullen), lbs/iu.2 9A 15 Opacity, Percent 85.4 55.2

To determine rate of solution, a bar of the soap in question can be rubbed. in uniform` manner with a wet sponge and the amount of soap rubbed` off per stroke can be determined. In like man;

originally in omega, delta or beta phase, is sube" jected to shearing forces and high pressure so' that milled soap properties are produced, there is a' change in state of at least a portion of the liquid which is present in the system. This change is interpreted as indicating that the liquid, which at normal temperatures is present as an isotropic dilute soap solution, is by the mechanical working and compacting brought into a more intimate association with the solid soap crystals which are present, becoming more closely andy tightly bound thereto by adsorption forces. Its vapor pressure is lowered and its freezing` behavior is altered. The changes which take place are most easily detected and followed by dilatometric measurements, which show the changes in volume which occur on gradually Warming such systems. rlhe soap is rst frozen by thrusting into a bath of alcohol and Dry Ice teristic of the soap, identifying its phase, but .also` rings .Y characteristic of ice, :showing `that water When soap in the system is frozen. On gradually warming the frozen system, there is rst an almost linear expansion (due to expansion of both ice and soap crystals), gradually giving way to a net contraction as the ice progressively melts. When melting is complete (accompanied by disappearance of X-ray diffraction lines characteristic of ice), a sudden break appears in the dilatometer curve, followed by resumption offlinear expansion with rising temperature, due to expansion of the co-existing soap solution and soap crystals. The sharp inflection of the curve, amounting to a change in sign of the volume change, marks the disappearance of the last trace of ice, and the temperature at which this occurs we shall call the thaw point.

In solid soaps containing more than about 40% water, the thaw point approaches the freezing point of water, but with decreasing water content, the thaw point decreases and the deviation from C. becomes easily measurable. Mere conversion from one phase to another, as for example from omega to opaque beta phase, is not accompanied by a change in thaw point, but the shearing-pressure treatment of our process which results in the milled soap properties of our products is accompanied by a readily detectable lowering of thaw point. The magnitude of this change is indicative of the effectiveness of the treatment.

The crystals of milled soaps are oriented predominantly in the direction of extrusion, as can be demonstrated microscopically with polarized light. This is done 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, rst with the section of soap turned to the position of maximum light extinction, and then turned 45 from that position. The increase in light transmission in the second position is indicative of the orientation of the particles of the specimen and distinguishes milled and extruded soaps from framed soaps.

We have described above means of measuring certain milled soap characteristics. Among other such characteristics which are less readily susceptible to quantitative measurement are uniformity of texture, smooth waxy feel, glossiness, tendency to swell when soaked in water and yet to return to substantially the original shape and appearance after drying, and freedom from warping during aging. These are characteristics which are easily recognizable when our product is compared with framed soaps of the same composition.

Most observations which are available as criteria for the existence or non-existence of characterizing milled soap properties are more easily applicable to bar soap than to soap in flake or other comminuted form. However, comparisons of rate of solutions, of translucency, and of rmness can also be made on flakes, and X-ray studies to determine phase and dilatometer runs to determine thaw point can be made on the soap irrespective of its form. We specifically contemplate in our invention soap possessing milled soap characteristics, but in particulate forms such as ilakes, granules, powders, lumps, threads, etc. as well as in the conventional milled soap bar form.

ELECTROLYTE AND WATER CONTENT OF COMPOSITIONS OF THE INVENTION In contrast to the prior art, according to which milled soaps are prepared from soaps containing less than about 20% water and less than about 1 sodium chloride, our invention provides milled soaps of up to or 40% water and of high salt content. The heart of our invention is in the relationship between water, salt and soap content, and our discovery of the range of ratios of those to one another within which range milled soaps can be made by our process. If, with high water content, the salt content is too low, a soft, opaque soap in delta phase is commonly obtained, which swells little and cracks badly when soaked in water, which is diiiicultly soluble and which lathers poorly as a result of the dimculty of removing soap from the wet bar by rubbing. If, on the other hand, the salt content is too high, a bar is obtained which is opaque, tends to crumble badly, has little power to pick up'water or swell when soaked, is not readily soluble, is poor in lathering power, and is commonly predominantly omega. The limiting salt and water content of soaps which are capable of conversion to the milled soap type by our process will be discussed more explicitly hereinafter.

Adjusting the salt and water content of our soaps so that they are properly related, and subjecting the adjusted system to mechanical working and compacting to convert it into the beta phase are not sufficient in themselves to insure that a soap of the milled type will result. Temperature also must be maintained within an optimum range. We have experienced diliculty in practicing our invention below about 80 F. or above about 125 F., these being the approximate limits within which soaps are producible which have the plastic solid consistency which permits milling, plodding, extruding and like shearing treatments under pressure. If, during the mechanical working, the soap is too hard, satisfactory pressure-welding to a coherent mass is not attained; if it is too soft (as, for example, when it is in pumpable condition or when its form andv shape can be influenced by the action of gravity or slight pressure) the finished product will be lacking in important milled soap properties such as translucency, glossiness, waxiness, substantial orientation of the grains or crystals in one direction, firmness, and marked power to imbibe water when soaked therein. The limiting temperatures and the optimum temperature in each particular case are dependent upon the salt and water content and also upon the fat formula of the soap. Thus in general, the higher the titre of the fatty acids of the soap, the higher the temperature required to produce from it a high moisture milled type of soap.

In our soap compositions, any other soap-compatible sodium salt can be substituted for sodium chloride inthe proper amount. By soap-compatible salt we mean one which does not convert soap into fatty acid or acid soap. Thus sodium acid sulfate and monosodium dihydrogen orthophosphate are examples of soap-incompatible salts, while among soap-compatible salts are sodium chloride, sodium carbonate, trisodium orthophosphate, tetrasodium pyrophosphate, pentasodium tripolyphosphate, borax and the various commercial forms of sodium silicate, ranging in SiOzzNazO ratio from about 2:1 to about 4:1.

Many of these soap-compatible sodium salts are widely used as soap builders, which aid in watersoftening, in increasing sudsing and washing power or in other respects, and one of the objects of our invention is to produce built soaps which possess typical milled soap properties in characterizing degree.

These soap-compatible salts have in varying degree the power to grain out or salt out molten soapv in the kettle, the absolute amounts required lily differing for different salts and for different soaps, but they amounts of any of the salts relative to each other being practically the same irrespective of the particular soap in question. In a somewhat analogous Way, these salts affect those properties of high-moistureV plastic solid soaps which determine Whether or not milled soap characteristics are producible therein by a shearing and pressure treatment.

In order to practice our invention with soaps of from 20% to 40% Water content, it is in general necessary to adjust the salt content to about 1% to 12% by Weight, the remainder being substantially all soap. The various salts are of varied effectiveness-With respect to milled soap properties; Afor each there is a range of ratios of salttsoapwvater Within Which milled soap properties are producible by shearingT treatment and pressure. These ranges can be defined by means of graphs in which the salt content is plotted as ordinate against the Water content as abscissa. By subtracting the sum of the salt and Water contents from 100%, the approximate per cent real soap is arrived at, subject to minor corrections for fractional percentages of glycerin, unsaponiable matter, carbonated alkali, etc. which may be present. Figs. l, 2, 3, 4 and 5 are such graphs for ve common salts, sodium chloride, pentasodium tripolyphosphate, tetrasodium pyrophosphate, trisodium orthophosphate and sodium silicate. Fig. 5 is found generally applicable with sodium silicates having a SiOzzNazO ratio oi from about 2.5:1 to about 3.521. On each of these graphs, there is an area A Within which our novel invention can be practiced. With higher salt or Water contents, our invention can be prac-y ticed only With difficulty or not at all, the products cf the shearing and pressure `treatment being deficient in characterizing milled soap properties. By Way of illustrating the use of these graphs, reference is made to Fig. l. If it is desired to make a milled type of soap having a moisture content of, for example, 35%, the salt content should be adjusted to between 1.6% and 4.35%.

These graphs are intended to serve as guides for the .processing of the typical soap under discussion, the optimum values in any particular case .being readily determinable as judged by the previously mentioned product characteristics. Generally speaking, for any desired moisture content Within the range yof the invention suitable salt contents lie on and close to a straight line drawn from the origin (20% moisture, 1% salt) to the diagonally opposite corner of `the area A, and salt contents further removed from this line should be employed with some caution.

SUITABLE FAT STOCKS FOR SOAPS OF THE INVENTION While reference has been made heretofore to a sodium soap from 80% tallow and 20% coconut oil, and While this formula yields a high moisture bar of particularly ydesirable properties, formulae of about 70% to 85% tallow and about 15% to 30% coconut oil are well suited for such bars, Such soaps are preferably extruded or milled at about 100 to 125 F., and when given mechanical'working and compacting at such temperatures they can be converted predominantly into the beta phase (i. e. more than 50% beta as determined by X-ray analysis), and typical milled soap properties can be imparted to them. With increasing amounts of coconut oil above about 1/3 of the iat formula, it becomes increasingly `difficult to convert the soap into the milled soap type, although formulae of as high as 50% coconutoil can be employed. When the coconut oilpercentagein ,the stock formula much exceeds 50%, the soapsthus produced are in many cases no longer predominantly in the beta phase or characterized by the described` milled soapproperties.

We are here using coconut oil as a specific example, but generally similar considerations apply when otheroils of the coccnut oil group are substituted v'for coconutoil. Byoilsof the coconut oil group wemean to designateall vegetable seed oils or fats at least 50% by Weight of the combined fatty acids of which are lauric and/or myristic acids.r These oils (many examples of Which are given in Icllditchs The Chemical Constitution of Natural Fats, second edition (1947), pages 198-205) are commonly derived from seed of members of thebotanical families Lauraceae (tangkallak kernel -oil for example), Myristicaceae (ucuhuba nut oil for example), Vochysiaceae (jabotyV kernel oil for example), Salvadaraceae (khakan kernel oil for example), Simarubaceae (dilra nut oil for example), and more especially the Palmae family. Coconut oil is the outstanding example of an oil derived from the seed of the Palmae family, but other non-limiting examples of such oils are oils of murumuru, tucuma, cohune, ouricoury, babassu and palm kernel.

' The factor determining whether or not a given fat will yield a soap Which can readily be converted predominantly into beta phase and which will have typical milled soap properties, isnot the particular source of the fat, but rather the composition of the combined fatty acids therein. Thus While itis possible to practice our invention with soap from stock mixtures containing more than 50% by Weight of some of lthe oils of the coconut oil group, we have in general experienced difliculty in accomplishing the objects of our invention when more than about 4.0% by Weight of the fatty acids of the soap are saturated fatty acids of less than 16 carbon atoms. Tallow, grease and palm oil are examples offats which, either alone or mixed with each other or with coconut oil, can be used for making the soaps of our invention. Highly unsaturated vegetable or marine oils are partially hydrogenated if they are to be used in any substantial proportion in the fat stock, since Without hydrogenation their soap is too soft 'to be suitabiecfor our treatment. They can, however, be mixed in limited proportions with other .more highly saturated fat. In general, in order that our process be successful, `the soap should be made of fats of more than 25 iodine value Which contain not more than 40% saturated fatty acids of Vless than 16 carbon atoms and'at least 20% by Weight of saturated fatty acids of 16 to 22 carbon atoms.

As in the case of conventional milled soap manufacture, ra limited substitution of potassium for sodium as the soap cation ,is permissible in the `practice of our invention, so long vas this substitution is not so great as to deprive the product of characteristic milled soap properties. In the same fashion potassium salts may be substitutedfor a portion of the sodium salts. Similar considerations apply in the case of .other soapmaking cations, such for example as the ammonium ionwor substituted ammonium ions (e. g. triethanolamine soaps).

EXAMPLES The following examples are illustrative of our process and of the detergent products made thereby, but it is to be understood that they are illustrative only and that our invention is not limited thereby but only by the terms of the appended claims. Examples have been selected in which the shearing forces and pressure were obtained by and during extrusion, such selection being made because of the more precise control and measurement of temperature, moisture content and pressure which are possible in extrusions. However, it will be understood that other means of applying shearing forces under pressure are feasible, such for example as milling and plodding. Unless otherwise noted, the extrusions of the examples were through a small cylindrical orifice leading from a soap-filled chamber into another chamber, one wall of each chamber being movable and consisting of the face of a hydraulically operated piston. The two pistons move synchronously, but the pressure on each is independently controlled. Hence the soap is extruded from one chamber at high pressure into another chamber at a pressure which is lower but suiiicient to mold the soap into a coherent bar suitable for stamping in conventional manner. When such soap is heated to the molten condition and then allowed to solidify by cooling to room temperature without agitation, it is referred to as framed soap.

Example 1.-Soap was made by the conventional boiled, settled process from a stock formula of:

23% coconut oil 20.0% marine oil, hydrogenated to 70 iodine value 22.8% tallow 28.5% lard 5.7% palm oil To the molten kettle soap, which contained 0.4% sodium chloride and about 30% water, there was added in a crutcher enough sodium chloride to bring the salt content to 2.75%. The hot mixture was allowed to cool to room temperature and solidify. It was then forced back and forth 24 times from one chamber into another through a slit orice 11/2 "xlzJ in cross section. The pressure on the high pressure side of the orice was from 580 to 640 lbs/in.2 and that on the low pressure side was 210 lbs./in.2. The chambers, ram, oriiice walls and soap were maintained at 110 F. by water-jacketing. The resulting bar of soap formed under pressure in the extrusion chamber was smooth, firm, homogeneous, waxy and translucent. It lathered freely on the hands, was subject to great swelling when soaked in water but returned to substantially its original shape and appearance when dried. Its breaking strength was 29 lbs/in.2 when measured by the Mullen tester. X-ray analysis showed it to bein the beta form, whereas a corresponding fram-sample was approximately 50% beta and 50% omega. The extruded bar was tested mechanically for rate of wear and lathering power by subjecting it to the mechanical action of a motor driven brush and a stream of water under controlled conditions and determining the amount of soap in the lather formed by this treatment in a fixed length of time. The amount was half again as great as in the case of another bar of the same soap, containing 2.75% NaCl, which was poured The mixture hydrogenated to 49 iodine value into a frame while molten and allowed to cool slowly to lroom temperature without agitation; it was 92.5% as great as the amount obtained in a parallel test on a commercially milled, plodded and stamped soap of the same fat formula containing 14% water, 0.38% NaCl, 0.12% NazCOa and 0.2 sodium silicate.

Example `2.Another lot of the molten kettle soap of Example 1 was partially dried and was adjusted in a crutcher to a sodium chloride content of 1.5% and a water content of 22.2%. This soap was cooled in a frame and was then extruded under the same conditions as in Example 1 except that the pressure on the high side was from 675 to 840 lbs/in.2 and that on the low side was 188 lbs./in.2. The resulting bar of soap was more waxy and translucent in appearance than that of Example 1, and firmer in consistency (Mullen test 68 lbs./in.2). It was in the beta phase, while the corresponding framed blank was in the omega phase. The rate of wear was 220% as great as that of the commercial milled blank. The extruded bar possessed milled soap characteristics such as swelling in water without much cracking or disintegration, and it returned tosubstantially its original shape and appearance on drying.

Eample 3.-A mixture of of mixed tallow and grease and 20% coconut oil was saponified with caustic soda according to the conventional boiled, settled process. The mixture of fats had an iodine value of 47.5, saponiiication value of 214.3 and titer of 38. To the molten soap in a crutcher, salt and water were added to adjust the mixture to 32.4% H2O and 3.8% NaCl. It was framed and then extruded 40 times at 90- F. through 122 round orifices in diameter. The resulting bar of soap was smooth, homogeneous, translucent and waxy in appearance, free-lathering, firm and in the beta phase.

Example 4 Another lot of the kettle soap of Example 3 was partially dried and was then adjusted in the crutcher to 26.4% H2O and 3.8% NaCl. It was then treated as in Example 3 except that the extrusion was at F., at a pressure of 12,500 lbs/in.2 and through a single orifice als in diameter. The resultant soap bar was like that of Example 3, in that it was in beta phase and possessed similar milled soap characteristics.

Example 5.-Soap was made by the usual boiled, settled process from 80% mixed tallow and grease and 20% coconut oil, the mixed soap stocks having iodine value 42.6, saponiication value 213.2 and titer 38.7. To the molten soap in a crutcher, salt was added to bring the composition to 29.5% water content and 1.6% NaCl content. After framing and cooling, the soap was extruded through 122 orifices 2 in diameter. Extrusion was at 85-95 F. and was repeated 40 times. The result was a translucent bar of soap, smooth and waxy in feel and appearance, rin, free lathering, in beta phase and obviously of a milled soap type.

Eample (i1-Soap was made by the conventional boiled, settled process from a mixture of tallow, grease and coconut oil, the mixed stocks having an iodine value of 41.4, saponification value of 213.8 and titer 39.3. The molten soap in a crutcher was adjusted to a water content of 31.2% and a salt content of 2.43%. 1t was framed and then extruded 40 times at 80-90 F. through an orifice 15 in diameter, at a pressure of about 12,500 lbs./in.2.' 'I'he resulting soap was in the beta phase and possessed the translucency,

A firmness free lathering ability, ready solubility asserita-f ties characteristic of milledso'ap.

Example. 7;-Tallow kettle-soap'was mixed virithe crutcher with Water and trisodiurn-orthophosphate and then'allowed to cool' andvsolidify to a.

iinal content of 33.5% Water', '7.5% NasPOi and 0.58% NaCl. 80 F. through aim" orifice at ay forward pressure of 1500 lbs/in.v2 and a back pressure of' 75 lbs/in?. The resulting bar washsmooth, homogeneous, rm, translucent and readily soluble in water, and was in the beta phase.

Examplel 8.--Tallow soap, made by the usual soap boiling method, was mixed` in a crutcher with commercial sodium silicate having a SiOfi-:NazOv ratio of 2.5821. The crutcher mixture was solidiiiedI by rapid cooling with slight separationof liquid and the solid soap was then extruded 40 times through a 1%54 orice at 80 F. to form aA bar, the forwardY pressure being 245i lbs/in.2 and the back pressure in the chamber in which the bar of soapwas molded'being 100 lbs/in?. The resulting bar contair1ed8.5%v silicate solids, 0.43% NaCl and 36.2% H20; was in beta phase and possessed characteristicv milled soap properties.

Example 9.-'I'he kettle soap of Example 'vwas mixed in the crutcher with tetrasodium pyrop-hosphate and additional sodium chloride and v water. Thevcrutched mixturewas solidified rapidly by cooling, withronly minor separation of liquid, andl was then extruded 40 times through a 1%;4" oriiice at 110 F., the forward pressure being 105 lbs/in.2 and thebackl'pressure being l lbs./in.2. The resulting bar contained 10% NaiPzOv, 3.48% NaCl and 37.2% H2O. It was in beta phase andi possessed characteristic milled soap properties.

Example ds-Another batch of thelkettle-soap of Example 1 was flash dried and' then mixed in a crutcher with tetrasod-ium pyrophosphate and water to a final composition off5% Na4P207.' 0.48% NaCl and 22.2% H2O. It was then framed and extruded 40'times throughV a slit orifice at a pressure of 490 to 640 lbs/in.2 on the high side and 121 lbs/in.2 on the low side, the temperature being 115 F. The resulting bar possessed typical milled soap properties.

ExampZe'11.-Another lot of themolten kettle soap of Example 1 was mixed ina crutcher with pentasodium tripolyphosphatev tov a composition containing 5.0% tripolyphosphate and 27.2% H2O. It was cooled in aframe'until solid and was then extruded 24 times at 100 F. through a slit orifice, from a high pressure of' 566 to 604 lbse/inf to a low pressure of 143 lbs/in?.4 The resulting bar of soap was in beta phase. It was transv lucent, rm (Mullen breakingl test', 46 lbs./in.2),

waxy, etc., being a typical milled soap inproperties.

Example 12.-Thi's example corresponds to Example 11 except that the nal-compositioncon tained sodium tripolyphosphat'e and 28.4%

It was then extruded 40 times at 1 H2O. The final soap was in beta phase and possessed the characteristic milledl soapproperties described in Example 11, although it'- was'V slightly softer than the soap of Example 11.

In the foregoing examples one can successfully employ milling andvplodding insteadof the y repeated extrusions which we have described. Due'precautions should be taken to provide ade--I quate working of the soap .and to .avoids excessivekk moisture loss.

Having thus described our-invention, what-'we claim.. and. desire' to" secure-.byn Letters Patent is:

lr6 1. In the process ofapreparing a detergent product of milled soap properties from a mixture of water",` soap-compatible sodium'saltA possessing the power to"saltou moltenvr neat soap in the kettle,gand a soap ora fat stock of iodine value above'25 not morethanv 40% of the combined fattyaci'dsw of"whichare saturated and of less thanv 16' carbon' atomsv4 and at least 20% of the combinedl fatty acidsA of whichtare saturated and offrom 16 vtoi 22 carbon atoms, the steps which comprise (a) adjusting' the salt content of the mixture to' from 1% to 12% and the water contentto from 20% to.40.% by weight, said contents being vso related that .milledsoap .properties are producibl'e inthe mixture by kneading, shearing and" c'ompacting` treatment'under pressure at a temperature below its solidiiication temperature, and: 1(12) subjecting said adjusted mixture in the plastic. solid condition to kneadingshearing and compacting. treatment under pressure at a temperature within the range oi about to about Fjandv such that the mixture is below its sol'idi'fication.` temperature and below that at which neat soap can exist instable equilibrium in the system but above the temperature at which itbecomes brittle, wherebya product is produced the. soap inwhich iswaxy, translucent and predominantly in the beta phase.

2'.' The process. o claim 1` wherein the salt is a-memberof thegroup consisting of sodium chloride, tetrasodium pyrophosphate, trisodium orthophosphate, pentasodium tripolyphosphate, sodiumsilicate having a SiOzzNazOratio of from 2:1 to 4:1" and mixtures thereof.

3. The process of claim 1 wherein the salt is sodium chloride and the electrolyte and. water contentslie. within@ area.. A. of Fig.. l hereof..

4. The process of. claiml wherein. the salt is tetrasodium; pyrophosphate andV theelectrolyte and water contentslie WthinareaA. oiy Fig.-2.

5. The process of claim 1 wherein the salt is pentasodium' tripolyphosphate and the electrolyte and'water contentsv liefwithin arear A of Fig: 3.

6:'Th'e process ofclaim lV Whereirrthe saltis trisodium orthophosphate and the electrolyte and watercontents' lie'within area A oi Fig. 4.

7. The processA ofl claim 1 wherein the salt is sodiumy silicate havinga SiOzzNa'zO ratio of from 2.5":'1' to 3.5 zl' and the' electrolyte and water contents lie withinarea A offFig; 5.

8. The process of claim 1 wherein` the mixture isv subjected' to shearing forces under pressure at a temperature within the rangel in which the mixture is a plastic solidA composed essentially of`r solid soap crystals andl nigre.

9. Thel process.y of preparingtoilet soapv bars which comprises'mechanicallyworking and compacting a mixture ofwater, soap-compatible' sodium salt possessing the power to salt out mol'- ten' neatvr soapY in the kettle, and soap of a fat stock of 'iodine value above 25 not more lthan 40% of the combined fatty acids of which are saturated andof! less than-16 carbon atoms and at least. 20% ofthe'. combined fatty acids of which areisaturated and of' fromv l6-Ato 22- carbon atoms, theconcentration of water beingv from 20% to 401% and thatof salt from 1% to 12% thereof by-weght', saidco'ntents being so proportioned that-milled soap-properties are producible in the mixtureby mechanical working, kneading and compacting, said working, kneading and compactingl being -aty af temperature of about' 80 to 125 F. andsuch thattthe mixture is below its solidic'ation peint' arrd-- is" a plastic' solid, andl 10. The process of preparing high-moisture milled type of toilet soap from a mixture of soap,

Water and sodium chloride, the soap being the sodium soap of a mixture of about to 30% coconut oiland about 85% to 70% tallow, which process comprises adjusting the water and salt content of said mixture to a point within area A of Fig. 1 hereof, milling said adjusted mixture in plastic solid condition ata temperature which is below its solidiiication point and is between about 100 to 125 F., and extruding the soap within said temperature range in continuous bar form through an orifice of restricted area, whereby a visually homogeneous extruded bar of milled soap characteristics is produced, the soap therein being waxy, translucent and predominantly in the beta phase.

11. A high moisture detergent having milled soap characteristics and consisting essentially of soap which is predominantly sodium soap of a fat stock of iodine value above 25 at least 20% of the combined acids of which are saturated and of from 16 to 22 carbon atoms and not more than 40% of the combined fatty acids of which are saturated and of less than 16 carbon atoms, soapcompatible sodium salt possessing the power to salt out molten neat soap in the kettle and Water, the Water content being from to 40% and the salt content being from 1% to 12% by weight thereof, soap constituting substantially all of the remainder of the detergent, the said soap being waxy, translucent and predominantly in the beta phase.

12. A high moisture detergent having milled soap characteristics and consisting essentially of soap, water, and at least one member of the group of salts consisting of sodium chloride, tetrasodium pyrophosphate, pentasodium tripolyphosphate, trisodium orthophosphate, and sodium silicate having a SiOzzNazO ratio of from 2:1 to 4:1, the water content being from 20% to 40% and the salt content being from 1% to 12% by weight of the detergent, soap constituting substantially all of the remainder of the detergent, said soap being the sodium soap of a fat stock of iodine value above 25, at least 20% of the combined fatty acids of which are saturated and of from 16 to 22 carbon atoms and not more than 40% of the combined fatty acids of which are saturated and of less than 16 carbon atoms, and said soap being waxy, translucent and predominantly in the beta phase.

13. A high moisture detergent having milled soap characteristics and consisting essentially of soap which is predominantly soap of afat stock of iodine value above at least 20% of the combined fatty acids of which are saturated and of from 16 to 22 carbon atoms and not more than 40% of the combined fatty acids of which are saturated and of less than 16 carbon atoms, Water and sodium chloride, the water and sodium chloride contents being such as to lie within area A of Fig. 1 hereof and soap constituting substantially all of the remainder of the detergent, the said soap being waxy, translucent and predominantly in the beta phase.

14. A high moisture detergent having milled soap characteristics and consisting essentially of soap which is predominantly soap of a fat stock of iodine value above 25 at least 20% of the combined fatty acids of which are saturated and of from 16 to 22 carbon atoms/and not more than' the detergent, the said soap `being waxy, translucent and predominantly in the beta phase.l

15. A high moisture detergent having milled soap characteristics and consisting essentially of soap which is predominantly soap of a fat stock of iodine value above 25 at least 20% of the combined fatty acids of which are saturated and of from 16 to 22 carbon atoms and not more than 40% of the combined fatty acids of which are saturated and of less than 16 carbon atoms, Water and pentasodium tripolyphosphate, the water and pentasodium tripolyphcsphate contents being such as to lie within area A of Fig. 3 hereof and soap constituting substantially all of the remainder of the detergent, the said soap being waxy, translucent and predominantly in the beta phase. I

16. A high moisture'detergent having milled soap characteristics and consisting essentially of soap which is predominantly soap of a fat stock of iodine value above 25 at least 20% of the combined fatty acids of which are saturated and of from 16 to 22 carbon atoms and not more than 40% of the combined fatty acids of which are saturated and of less than 16 carbon atoms, water and trisodium orthophosphate, the water and trisodium orthophosphate contents being such as 'to lie within area A of Fig. 4 hereof and soap constituting substantially all of the remainder of the detergent, the said soap being waxy, translucent and predominantly in the beta phase.

17. A high moisture detergent having milled soap characteristics and consisting essentially of soap which is predominantly soap of a fat stock of iodine value above 25 at least 20% of the combined fatty acids of which are saturated and of from 16 to 22 carbon atoms and not more than 40% of the combined fatty acids of which are saturated and of less than 16 carbon atoms, water and sodium silicate having a SiO2INa2O ratio of 2.521 to 3.521, the Water and sodium silicate contents being suchas to lie within area A of Fig. 5 hereof and soap constituting substantially all of the remainder of the detergent, the said soap being waxy, translucent and predominantly in the beta phase.

18. A high moisture toilet soap bar of milled type consisting essentially of a mixture of soap, Water and sodium chloride, the soap being the sodium soap of a mixture of about 15% to 30% coconut oil and about to '70% tallow, the salt and water content of said bar lying Within area A of Fig. 1 hereof and soap constituting substantially all of the remainder of the bar, and being predominantly in the beta phase, said bar being of the milled soap type and being firmer and more translucent than is the same bar after being melted and resolidied without agitation and the soap in said bar being predominantly in the beta phase.

19. In the process of preparing a detergent product of milled soap properties from a mixture of Water, a soap-compatible sodium salt selected from the group consisting of sodium chloride, tetrasodium pyrophosphate, trisodium orthophosphate, pentasodium tripolyphosphate and sodium silicate having a SiOzzNazO ratio of from 2:1 to

19 411 .and Soap which predominantly vsodium Soap of a vfat stock of iodine value above 25 at least 20% of the combined fatty acids of which are saturated and of from 16 to 22 carbon atoms and not more than 40% of the combined fatty acids of which are saturated and of less than 16 carbon atoms, the steps which comprise (la) adjusting the salt content of the mixture between l and 12% and the Water content between 20 and 40% by Weight so as to produce a mixture the composition of which lies close to a straight line extending from the origin represented by 20% moisture, 1% salt to the diagonally opposite corner of area A of that one of the graphs in Figures 1-5 which applies te the particular salt selected, and (b) subjecting vsaid adjusted mixture in the; plastic solid condition to kneading, rshear-- ing and ompacting treatment under pressure at a temperature below its solidiication temperature and in the range of substantially 80 to substantially 125 F., whereby a product is produed the soap in which is waxy, translucent and Dredominantly in the beta phase.

References Cited in the file rof this patent UNITED STATES PATENTS Number Name Date 2,295,594 Mills Sept. 15, 1942s 2,316,689 Heald et al. Apr. 13, 1943

Claims (1)

1. IN THE PROCESS OF PREPARING A DETERGENT PRODUCT OF MILLED SOAP PROPERTIES FROM A MIXTURE OF WATER, SOAP-COMPATIBLE SODIUM SALT POSSESSING THE POWER TO "SALT OUT" MOLTEN NEAT SOAP IN THE KETTLE, AND A SOAP OF A FAT STOCK OF IODINE VALUE ABOVE 25 NOT MORE THAN 40% OF THE COMBINED FATTY ACIDS OF WHICH ARE SATURATED AND OF LESS THAN 16 CARBON ATOMS AND AT LEAST 20% OF THE COMBINED FATTY ACIDS OF WHICH ARE SATURATED AND OF FROM 16 TO 22 CARBON ATOMS, THE STEPS WHICH COMPRISE (A) ADJUSTING THE SALT CONTENT OF THE MIXTURE TO FROM 1% TO 12% AND THE WATER CONTENT TO FROM 20% TO 40% BY WEIGHT, SAID CONTENTS BEING SO RELATED THAT MILLED SOAP PROPERTIES ARE PRODUCIBLE IN THE MIXTURE BY KNEADING, SHEARING AND COMPACTING TREATMENT UNDER PRESSURE AT A TEMPERATURE BELOW ITS SOLIDIFICATION TEMPERATURE, AND (B) SUBJECTING SAID ADJUSTED MIXTURE IN THE PLASTIC SOLID CONDITION TO KNEADING , SHEARING AND COMPACTING TREATMENT UNDER PRESSURE AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 80* TO ABOUT 125* F. AND SUCH THAT THE MIXTURE IS BELOW ITS SOLIDIFICATION TEMPERATURE AND BELOW THAT AT WHICH NEAT SOAP CAN EXIST IN STABLE EQUILIBRIUM IN THE SYSTEM BUT ABOVE THE TEMPERATURE AT WHICH IT BECOMES BRITTLE, WHEREBY A PRODUCT IS PRODUCED THE SOAP IN WHICH IS WAXY, TRANSLUCENT AND PREDOMINANTLY IN THE BETA PHASE.

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