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Publication numberUS3814698 A
Publication typeGrant
Publication dateJun 4, 1974
Filing dateJan 10, 1972
Priority dateJan 10, 1972
Also published asCA1021658A, CA1021658A1, US3941712
Publication numberUS 3814698 A, US 3814698A, US-A-3814698, US3814698 A, US3814698A
InventorsBarnes C, Dalby G, Ferrara P, Gordon R
Original AssigneeBarnes C, Dalby G, Ferrara P, Gordon Roy Gerald
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Soap composition and process of producing such
US 3814698 A
Abstract
Solid soap such as framed or milled toilet soap, which is conventional in all aspects except that it contains as part of its composition 5 to 100 percent, based upon the weight of free fatty acid components, of at least one "bath oil." The solid soap composition is produced by first saponifying an appropriate fatty acid or mixture thereof in the usual way, solidifying the saponified material by cooling, extruding ribbons of solidified material, drying the extrudate, and then framing the dried extrudate into soap bars. The process hereof differs from this "usual" process in that bath oil, in whatever quantity is desired, is added to the liquid saponification mixture, rather than just prior to the framing step as in the prior art.
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United States Patent US. Cl. 252-370 Claims ABSTRACT OF THE DISCLOSURE Solid soap such as framed or milled toilet soap, which is conventional in all aspects except that it contains as part of its composition 5 to 100%, based upon the weight of free fatty acid components, of at least one bath oil. The solid soap composition is produced by first saponifying an appropriate fatty acid or mixture thereof in the usual way, solidifying the saponified material by cooling, extruding ribbons of solidified material, drying the extrudate, and then framing the dried extrudate into soap bars. The process hereof differs from this usual process in that bath oil, in whatever quantity is desired, is added to the liquid saponification mixture, rather than just prior to the framing step as in the prior art.

This invention relates to soap. It more particularly refers to solid soaps, most especially of the milled type.

Milled soaps have been made for many years. It is usual to produce such soaps by liquifying a mixture of fatty acid, or acids, or glycerides thereof, and aqueous sodiumhydroxide solution at elevated temperatures; saponifying the fatty acid content of the warm liquid mixture; cooling the saponification mixture to a substantially solid, but suitably soft, condition; forming the solidified saponification mixture into a suitable shape, e.g. by extrusion into a ribbon or the like; drying the shaped extrudate to an acceptable moisture content; milling the dried soap with conventional additives and adjuvants such as dyes, pigments, perfumes and the like; and then forming the milled soap composition into bars or other desired shapes.

For many years it has been the desire of the soap industry to incorporate so-called bath oils or the emoluents into milled soap. To date it has only been possible, by presently known processes, to incorporate up to about 1.5%, based upon the weight of fatty acid, bath oil in milled soap. The soap industry would like to incorporate orders of magnitude higher proportions of bath oil in milled soap but to date has not been able to.

The known method of incorporating bath oil into milled soap is to do so during the above recited milling step. -It has been discovered that the problems of the prior art are at this point in the process.

It is therefore an important object of this invention to provide a novel process for incorporating bath oil into milled soap.

It is another object of this invention to provide a milled soap having a much higher proportion of bath oil incorporated therein than prior art soaps.

It is a further object of this invention to utilize as a bath oil in milled soap, a broad spectrum of esters, oils, long chain alcohols, waxes and the like.

It is a further object of this invention to utilize a wide range of ingredient proportions in the manufacture of bar soap containing high proportions of bath oil.

Other and additional objects of this invention will become apparent from a consideration of this entire specification including the claims hereof.

3,814,698 Patented June 4, 1974 In accord with and fulfilling these objects, one aspect of this invention resides in a novel milled soap, having constituents and proportions thereof conventionally formed in milled soap, which contains a high proportion of bath oil substantially homogeneously incorporated therein. While in the prior art it has been possible to substantially homogeneously incorporate only as much as up to about 1 /2 weight percent bath oil, there is apparently no upper limit on the proportion of the bath oil which is and can be homogeneously incorporated in the soap of this invention. The proportions of bath oil are not per se critical, although they do define a composition which is distinguished from the prior art. Any proportion of bath oil which exceeds that which the prior art could homogeneously incorporate in milled soap constitutes the lower limit of this proportion in this invention. Suitable lower limits may be 2, 3, 5 or 10 weight percent depending upon what the prior art says it can do. As noted above, as a practical matter milled soaps having 1 /2 percent bath oil are about as good as have been achieved commercially. As noted above, there is no real upper limit on the proportion of bath oil which can be substantially homogeneously incorporated in milled soap according to this invention. As a practical matter, however, proportions higher than about based upon the weight of fatty acid, are not praticularly advantageous in that at above these levels the bath oil starts to effect the lathering and cleansing qualities of the soap.

It is to be noted that the term bath oil as used herein is intended to represent those materials generally categorized under this heading in the soap and cosmetic arts. Exemplary materials which fall within this group are oils, esters, waxes and long chain alcohols such as isopropyl myristate, palmitate esters, laurate esters, lanolins, castor oils, mineral oils, C to C normal alcohols, and ethoxylated long chain linear alcohols of the type exemplified above. The ethoxylation may be with as little as one (1) or as much as five (5) moles of ethylene oxide (or glycol) per alcohol molecule. It should be understood that bath oils are per se known and those materials referred to above are exemplary and non-limiting. Tests, to be reported hereinafter, using isopropyl myristate are fully exemplary of this group of materials and the results reported are to be considered as representative of the entire group of water insoluble bath oils.

While the prior art has been generally unable to incorporate large proportions of bath oils into milled soap, this has been accomplished according to this invention by a change in the process of producing milled soap which change, in hindsight, may not appear to be that dramatic. Nevertheless, a most important aspect of this invention is in the process of producing high bath oil containing, substantially homogeneous, milled, solid soap.

As noted above, the prior art has always attempted to incorporate the bath oil during the milling step, which is the point in the processing at which other additives, such as colorants and odorants, are incorporated in the soap. The departure of this invention from the prior art is to incorporate the bath oil into the liquid saponification mixture before it has been solidified and/or dried.

While it is not really known why more bath oil can be homogeneously incorporated in milled soap by the process of this invention than the prior art techniques, it is thought that there may be some connection with the crystal structure of the soap.

The physical structure of soap has been researched by many scientific workers using a variety of techniques. The general conclusion is that soap is a solid solution with a complicated and hard to define lattice structure. By X-ray diffraction studies, electron microscopy and vapor tension data, it is apparent that the lattice structure is capable of physically incorporating or enclosing some molecules of water. It is generally agreed that the absorption of moisture by an over-dried soap flake or granule is exothermic and may produce enough heat to cause spontaneous combustion, particularly when large quantities of dry soap are stored in a confined area. This seems to reinforce the idea that water molecules do in fact become absorbed in the lattices or crystalline structure of the soap in question.

There is also agreement on the physical forms of the soap lattices and this is reflected in the literature accord on the four presently known phases of soap structure; namely, alpha, beta, omega and delta forms. The alpha phase is the least important in that it appears at very low levels in most soaps of commerce. It is believed the alpha phase has the lowest attractive forces for encompassing water, and, as its internal held water readily shifts to another soap phase, usually reduction in alpha phase shows up as an increase in the beta phase. Therefore most solid forms of soap may be considered as consisting of the other three phases. It is possible in producing a soap in solid form to vary the percentages of beta, omega and delta over a considerable range.

In the so-colled framed soaps, which are solutions brought to a solidification stage without agitation, the main soap lattice appears as the omega phase. The usual milled soaps are predominantly the beta phase. Milling and plodding result in the dominance of the beta phase. Even the framed soaps will show a shift from omega to beta on applying mechanical work such as milling and plodding. It is also known that in a rapid chilling of a framed soap the omega form will be by-passed and the product will be predominantly in beta form.

One of the interesting phenomenon of the framed soaps (sometimes transparent or translucent types) is the gradual loss of translucency if the corners or edge of a bar of soap are damaged with a sudden force such as by striking the corners against a hard surface. The introduction of even a few crystalline units of beta phase soap by this damaging force seems to result in a gradual conversion of the omega to the beta phase, with a corresponding loss in transparency values. A parallel case of beta crystals invading the province of the omega may be observed by making a composite bar by hydraulic pressing together the smooth faces of a frame soap and an ordinary milled soap. The rate of crystalline invasion will vary with a number of factors including moisture content, ingredients, hardness, etc. though a period lapse of 6-8 weeks is usually enough to reflect the shift in crystallinity of the beta phase in the framed portion of the composite bar.

The delta form appears to be an intermediate between beta and omega in terms of water solubility and lather capacity and also in terms of hardness.

Thhe main physical attributes of beta, omega and delta forms to a soap maker appear in the reaction of these forms when soaked in water. The beta form soap tends to absorb water readily as evidenced by swelling and its tendency to disintegrate. The omega phase is the least water soluble form, in terms of its response to water soaking, and gives practically no evidence of swelling. The delta phase has reactivity constants between beta and omega phases, with a tendency to form cracks or fissures with only a slight swelling.

Manufacturers of milled soaps have made numerous unsuccessful attempts to mill into the crystalline lattices of the usual soaps, a variety of water insoluble oils and esters, generally referred to as bath oils. The objective has been to incorporate into milled soaps enough bath oil substance to achieve a simultaneous soap bathing effect, and the covering of the body with a protective film of bath oil. The usual techniques require the production of soaps, and reducing the soaps to flakes, ribbons or chips to simplify the drying out to moisture levels between and 12%. On reaching these levels of moisture, the

flakes are put through milling rolls to incorporate ingredients such as pigments, opacifiers, fragrances and different colors. At this stage, an attempt is made to incorporate various and sundry bath oils. The inclusion of bath oils by these classic methods has been limited to levels of 1-l.5l% of weight of the soap. Additions in excess of 1.5% produced soaps that were soft and somewhat oily, with poor lathering ability. In terms of the soap tendency to disintegrate, it seemed obvious that the soap lattice had all the characteristics of the beta phase. This phase appears to resist the absorption of oils irrespective of moisture levels.

There has now been discovered a technique which enables the incorporation of relatively large percentages of bath oils, yet produces a milled soap with the desired physical properties and eminently suitable properties of bathing and laying on bath oils. By the use of our technique, bath oil additions measuring up to or more, based on the free fatty acid content, can be achieved. Such elevated levels are set forth merely to emphasize the extent to which the same ingredient compositions are compatible with very high levels of bath oils.

The very core of this invention is the discovery that if the bath oils are incorporated after the saponification step but prior to the formation of the crystalline phases such as those previously reviewed, then the crystalline phases which forms are predominantly the omega phases. The omega phase appears to have large and unexpected tolerance for bath oils. Not only does the omega phase have an unexpectedly high absorption capacity for bath oils, e.g. mineral oils, esters, alcohols, etc. but the omega crystalline lattice appears to be capable of withstanding a considerable amount of milling and plodding without the exudation or loss of oil, or diversion from the omega state.

The moisture content of the high oil soaps made by the procedure set forth in the preceding paragraphs may be reduced to levels of 5-l2% as preferred, by drying out soap noodles, flakes or ribbons through the conventional warm air heating type of apparatus.

Whether or not the theory, that the addition of bath oils right after saponification but prior to solidification is truly a matter of maintaining the soap lattices in the omega phase, is an exact representation of what takes place, may or may not be easily proven. The following examples and references however tend to support the omega phase theory or concept as an acceptable view.

One series of experiments serve to illustrate how the sequential process of putting the ingredients together produce soaps having the same composition chemically, but with surprisingly different properties. The variations in properties is thus a striking view of the effects of the particular crystalline lattices of the soap.

A batch of soap noodles was prepared by saponifying equal molar quantities of stearic acid and lauric acid with a stoichiometric equivalent of sodium hydroxide dissolved in a water solution. The ratios were 284 grams of stearic acid, 200 grams of lauric acid and 80 of sodium hydroxide (2 mols) in ml. of water-29 grams of glycerine were added to the molten fatty acids. The saponification was conducted at a temperature range of -200 F. The hot mixture was transferred to trays and cooled until well solidified, then extruded into ribbons for drying. The ribbons were dried to a moisture level of 10%. These ribbons were processed in the normal manner of soap making and produced firm bars with excellent sheen and superior lather and detergent effects.

Using the prepared ribbons of the preceding paragraph, we go to the first of our three experiments:

EXAMPLE 1 In this Example, 2000 grams -of the dried flakes were mired with 844 grams of isopropyl myristate and recycled through a mixing screw and pressed through a ploddenThemyristatewasaddedinincremmgmdthe product was recycled until the ester was completely taken up. Bars of soap made from the soap base plus myristate by this method were soft with an oily feel. When placed in water, the bars tended to disintegrate. The lathering capacity of the soap bars was retarded, and the detergency of the bars was less than satisfactory.

The bars of soap thus produced failed to improve on standing even as long as 6 months.

EXAMPLE 2 In this Example the same ribbons used in producing the base for the previous experiment, were handled in a different manner. The 2000 grams of soap ribbons and the 844 grams of isopropyl myristate were mixed together in a kettle and the mixture brought to a temperature of 240 F. At this temperature, the mix resembled the consistency of soft, mashed potatoes. The kettle was emptied and the contents placed on trays to solidify. The solidified mass was then processed into bars of soap in accordance with the same steps followed in Example 1. The bars of soap made according to this procedure were firmer than those made in the previous example, yet lacking in a full measure of the desired properties sought in a quality toilet soap.

EXAMPLE 3 In this Example, we will describe the formulation of an in situ soap composition, having the same proportion of ingredients as in the previous Examples 1 and 2.

We combined 568 grams of stearic acid and 400 grams of lauric acid. These were melted in a kettle along with 65 grams of glycerine. A sodium hydroxide solution containing 160 grams of alkali in 320 ml. of water was also prepared. The molten fatty acid and glycerine were brought to a temperature of 190 F. and the alkali added with vigorous agitation. When the saponification ingredients had been thoroughly mixed, 350 grams of isopropyl myristate was added (this corresponds to the 844 grams used per 2000 grams. In the previous Examples). Mixing was continued until the liquid phase of myristate had been incorporated in the saponification mixture.

The mash-potato like mixture was removed to trays and cooled. When cool, it was extruded into ribbons and dried to a moisture level of 10%.

Bars of soap made from a composition processed in the manner just described are outstandingly different from those covered in the prior Examples 1 and 2. The bars were firm, lathered well and produced a combination of detergency and residual oil feed that was notable. It is apparent therefore that this technology of producing a bath oil soap bar results in a combination of ingredients, and crystalline structure of superior characteristics.

These Examples were repeated with a number of bath oil ingredients as substitutes for the isopropyl myristate. These substitutions included palmitate and laurate esters, lanolins, castor oils, mineral oils, and a number of linear primary alcohols ranging in chain length from C to C Some of the linear alcohols were ethoxylated with various degrees of ethylene oxide substitution. In all cases, the same kind of differentiation as brought out in the 3 Examples was evident.

As a matter of indicating the extreme capacity of a soap base to absorb bath oils, tests were made where the ratio of bath oils to fatty acids were as high as 1.5 to 1.0. While these high ratios may be impractical from the standpoint of a commercially saleable bar because of economics, it is evident that the technology set forth herein is applicable to many soap formulations.

What is claimed is:

1. In the process of producing milled soap which comprises liquifying soap producing fatty acid or fatty acid glycerides, admixing a saponifying proportion of alkali therewith, saponifying said fatty acid or glyceride with said alkali at elevated temperatures, cooling said saponification mixture to a solidified state, forming said solidified saponification mixture into shapes suitable for removal of water, removing water from said shapes, and then milling said dehydrated soap shapes into substantially solid bar soap; the improvement, whereby incorporating unusually high proportions of from 5 to about 150% of a bath oil selected from the group consisting of isopropyl myristate, laurate esters, palmitate esters, waxes, castor oil, C to C normal alcohols and C to C normal alcohols ethoxylated with 1 to 5 moles of ethylene oxide, based on the fatty acid content in said milled soap, which comprises at mixing said bath oil withsaid liquid saponification mixture after the saponification step, but prior to cooling said mixture to a solidified state.

2. The improved process claimed in claim 1 including adding 5 to 50 percent bath oil, based on the fatty acid content of said saponification bath.

3. The improved process claimed in claim 1 wherein said fatty acid or glyceride are equimolar proportions of stearic and launc acid.

4. The improved process as claimed in claim 3 including adding about 3.5 to 4% glycerine to said saponification bath.

5. The improved process as claimed in claim 1 wherein the bath oil is isopropyl myristate.

6. A solid milled soap made according to the process of claim 1.

References Cited UNITED STATES PATENTS 3,179,596 4/1965 Farrar et al. 252 2,143,066 1/ 1939 Hampton 252-126 273,239 2/1983 Johnston 252-132 243,757 7/1881 Casamajor 252126 FOREIGN PATENTS 424,283 2/ 1935 Great Britain 252-122 1,043,453 9/1966 Great Britain 252122 HERBERT B. GUYNN, Primary Examiner D. L. ALBRECHT, Assistant Examiner U.S. Cl. X.R.

252-108, 132, 134, 368, Dig. 1, Dig. 5, Dig. 16

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4017573 *Jun 4, 1975Apr 12, 1977Colgate-Palmolive CompanyProcess for making variegated soap
US4017574 *Jun 4, 1975Apr 12, 1977Colgate-Palmolive CompanyProcess for making variegated soap
US4124521 *Oct 3, 1977Nov 7, 1978Revlon, Inc.Soaps containing encapsulated oils
US4285826 *Apr 14, 1980Aug 25, 1981Armour-Dial, Inc.Toilet soap bars imparting improved moisturing and skin feel characteristics
US4582626 *Jun 25, 1984Apr 15, 1986Ferrara Peter JSoap compositions and process with emollients, bath oils and polymeric ethylene oxide slip agents
US4808322 *Mar 10, 1988Feb 28, 1989Mclaughlin James HSkin cleansing-cream conditioning bar
US4874538 *Oct 23, 1986Oct 17, 1989The Procter & Gamble CompanyToilet soap bar compositions containing water soluble polymers
US4941990 *Feb 22, 1989Jul 17, 1990Mclaughlin James HSkin cleansing-cream conditioning bar
US5143639 *Sep 25, 1989Sep 1, 1992Aarhus Oliefabrik A/SUse of (C1 -C5) alkyl esters of aliphatic (C8 -C22) monocarboxylic acids for removing fat, inks and the like from printing machines
US5770556 *Mar 21, 1997Jun 23, 1998Lever Brothers Company, Division Of Conopco, Inc.Process for making bar compositions having enhanced deposition of benefit agent comprising use of specific spray dryable adjuvant powders
US5817609 *Jan 8, 1997Oct 6, 1998Lever Brothers Company, Division Of Conopco, Inc.Bar composition comprising low viscosity oils pre-thickened by non-antifoaming hydrophobic polymers
US5858939 *Mar 21, 1997Jan 12, 1999Lever Brothers Company, Division Of Conopco, Inc.Method for preparing bars comprising use of separate bar adjuvant compositions comprising benefit agent and deposition polymer
US5935917 *Nov 5, 1997Aug 10, 1999Lever Brothers CompanyBar composition comprising entrapped emollient droplets dispersed therein
US5972859 *Mar 28, 1997Oct 26, 1999Lever Brothers CompanyBar composition comprising entrapped emollient droplets dispersed therein
US6423672Apr 26, 2001Jul 23, 2002Unilever Home & Personeal Care Usa Division Of Conopco, Inc.Process for making soap bar comprising about 6% and greater triglycerides
US6440913Apr 26, 2001Aug 27, 2002Unilever Home & Personal Care Usa Division Of Conopco, Inc.Soap bar comprising about 6% and greater triglycerides which structure well and have desirable user properties
US6544938Oct 2, 2001Apr 8, 2003Unilever Home & Personal Care Usa, Division Of Conopco, Inc.Soap bar comprising high levels of specific alkoxylated triglycerides which provide enhanced sensory properties and process well
US20050159330 *Jan 14, 2005Jul 21, 2005Unilever Home & Personal Care Usa, Division Of Conopco, Inc.Detergent composition
EP0507559A2 *Mar 31, 1992Oct 7, 1992Unilever PlcDetergent composition
EP0507559A3 *Mar 31, 1992Jan 7, 1993Unilever PlcDetergent composition
EP0825252A1 *Aug 16, 1996Feb 25, 1998Unilever N.V.Process for preparing soap material
WO1989008444A1 *Feb 27, 1989Sep 21, 1989Mclaughlin James HNon-foaming skin cleansing-cream conditioning bar
WO1998007827A1 *Jul 23, 1997Feb 26, 1998Unichema Chemie B.V.Process for preparing soap material
WO2005068594A1 *Dec 18, 2004Jul 28, 2005Unilever PlcImproved detergent composition
Classifications
U.S. Classification510/152, 510/505, 510/459, 510/506
International ClassificationC11D9/48, C11D9/26, C11D13/00, C11D9/04
Cooperative ClassificationC11D9/267, C11D13/00, C11D9/48
European ClassificationC11D9/48, C11D13/00, C11D9/26F
Legal Events
DateCodeEventDescription
Jul 18, 1990ASAssignment
Owner name: EMILIA FERRARA LTD.,, NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:FERRARA, PETER J.;REEL/FRAME:005377/0929
Effective date: 19900702
Jul 18, 1990AS02Assignment of assignor's interest
Owner name: EMILIA FERRARA LTD., BOX 441, CORNWALL, NY 15218
Owner name: FERRARA, PETER J.
Effective date: 19900702
Jul 1, 1981AS02Assignment of assignor's interest
Owner name: BARNES CLARENCE A. JR.
Owner name: DALBY GASTON
Effective date: 19810108
Owner name: FERRARA, PETER J. RIDGE RD.CORNWALL, N.Y.
Effective date: 19800703
Owner name: GORDON ROY
Effective date: 19800708
Jul 1, 1981ASAssignment
Owner name: FERRARA, PETER J. RIDGE RD.CORNWALL, N.Y.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:BARNES CLARENCE A. JR.;DALBY GASTON;GORDON ROY;REEL/FRAME:003864/0351;SIGNING DATES FROM 19800703 TO 19810108