WO1998011864A2

WO1998011864A2 - Lathering and cleansing personal cleansing bar compositions which contain elongated lipid particles

Info

Publication number: WO1998011864A2
Application number: PCT/US1997/016610
Authority: WO
Inventors: Nicholas William Geary; Kasia Maria
Original assignee: The Procter & Gamble Company
Priority date: 1996-09-23
Filing date: 1997-09-19
Publication date: 1998-03-26
Also published as: WO1998011864A3

Abstract

Personal cleansing bar compositions which contain from 5 % to 40 % of lipophilic skin moisturizing agent particles, from about 1 % to about 50 % of a lathering surfactant and from about 10 % to about 50 % water. The lipophilic skin moisturizing agent particles are elongated as a result of being passed through a static mixer.

Description

LATHERING AND CLEANSING PERSONAL CLEANSING BAR COMPOSITIONS WHICH CONTAIN ELONGATED LIPID PARTICLES

TECHNICAL FIELD

The present invention relates to personal cleansing bar compositions which provide improved moisturization benefits to the skin The personal cleansing bar compositions of the present invention contain an emulsion component The emulsion contains lipophilic skin moisturizing agent particles which are nonspherical in shape. The emulsion composition is passed through a static mixer to achieve the nonspherical shape of the lipophilic skin moisturizing agent particles

BACKGROUND OF THE INVENTION

Personal cleansing bar compositions which deposit lipophilic skin moisturizing agents onto the skin and. thereby, provide a moisturization benefit to the skin are very popular with consumers Compositions which deliver effective amounts of lipophilic skin moisturizing agents to the skin have been disclosed in the art and are commercially available to consumers Nevertheless, some consumers would prefer to have an even greater moisturization benefit delivered from these moisturizing personal cleansing bar compositions

It has now been found that the deposition of a lipophilic skin moisturizing agent can be increased if at least about 10% of the lipophilic skin moisturizing agent particles having a diameter of greater than 10 microns present in the personal cleansing bar lather are nonspherical

SUMMARY OF THE INVENTION

The present invention relates to pour-molded, cleansing and moisturizing personal cleansing bar compositions which comprise 1) from about 10% to about 50% of a rigid semi-continuous, interlockmg open mesh crystalline network structure comprised of fatty acid soap, and 2) an unstable emulsion contained within the interstices of the open mesh crystalline fatty acid soap structure

The unstable emulsion comprises a moisturizing phase and an aqueous cleansing phase The moisturizing phase of the emulsions employed m the personal cleansing bar compositions of the present invention comprises from about 5% to about 40% by weight of the bar composition of lipophilic skin moisturizing agent particles At least about 10% by weight of the lipophilic skin moisturizing agent particles having a diameter of greater than about 10 microns present in the personal cleansing bar lather are nonspherical The aqueous cleansing phase comprises from about 1 % to about 50% by weight of the bar composition of a lathering synthetic surfactant and from about 10% to about 50% water

The nonspherical shape of the lipophilic sk moisturizing agent particles in die personal cleansing bar lather is achieved by passmg the particles through a static mixer DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to pour-molded lathering and moisturizing personal cleansing bar compositions which provide superior moisturization to the skin. The personal cleansing bar compositions of the present invention comprise 1 ) from about 10 to about 50% by weight of the composition of a rigid semi-continuous, interlocking open mesh crystalline network structure comprised of fatty acid soap, and 2) an unstable emulsion contained within the interstices of the open mesh crystalline network structure.

The unstable emulsion comprises a moisturizing phase and an aqueous cleansing phase. The aqueous cleansing phase comprises a lathering surfactant and water. The moismrizing phase comprises lipophilic skin moisturizing agent particles. At least about 10% by weight of the lipophilic skin moisturizing agent particles having a diameter of greater than about 10 microns in the personal cleansing bar lather are nonspherical, as determined by the % Nonspherical Particles Method set forth hereinafter in the Analytical Methods Section. For purposes of the present invention, a particle is nonspherical if it has a aspect ratio (length divided by width) of greater dian about 1.1. It has been found tiiat when at least about 10% by weight of the lipophilic skin moisturizing agent particles in the bar lather are nonspherical, that the personal cleansing bar composition will provide superior moisturization benefits to die skin. The nonspherical shape of the lipophilic skin moisturizing agent particles is achieved by passing the particles through a static mixer.

Personal cleansing bar compositions wherein at least about 10% by weight of the lipophilic skin moisturizing agent particles having a diameter of greater man about 10 microns contained in the bar ladier are nonspherical, including the material contained therein and processes for making them are described in detail as follows: I. Ingredients

A. The Unstable Emulsion

The personal cleansing bar compositions of die present invention contain an unstable emulsion which is contained within the interstices of the open mesh crystalline network structure. In order to deposit significant amounts of the lipophilic skin moismrizing agent panicles on the skin, it is important that the emulsion employed in the bar compositions herein be relatively unstable. The relative stability of die emulsion is determined by the Emulsion Stability Centrifuge Test set form hereinafter in die Analytical Mediods Section.

The emulsion employed in the personal cleansing bar compositions herein contain a moisturizing phase and an aqueous cleansing phase. Each of these phases of the emulsion is described in detail as follows:

1. Moisturizing Phase

The emulsion employed in die personal cleansing bar compositions of die present invention comprises a moisturizing phase which comprises lipophilic skin moismrizing agent particles. In particular, the personal cleansing bar compositions of the present invention comprise from about 5% to about 40%, preferably from about 10% to about 40%, more preferably from about 10% to about 30% by weight of the bar composition of lipophilic skin moisturizing agent particles

The lipophilic skin moisturizing agent particles provide a moisturizing benefit to the user of the personal cleansing product when the lipid moisturizing agent particles are deposited to the user's skm It has been found that deposition of the lipophilic skm moismrizmg agent is dramatically increased when at least about 10%, preferably at least about 30%, more preferably at least about 40%, and most preferably at least about 50% by weight of the lipophilic skin moismrizmg agent particles having a diameter of greater than about 10 microns in the bar lather are nonspherical In general, the larger the number of nonspherical lipophilic skm moismrizmg agent particles in the bar lather, the greater the deposition of the moismrizmg agent on the skm

The lipophilic skm moismrizmg agents suitable for use herem are those comprised of particles which are capable of being permanently stretched when they are passed through a Koch static mixer Suitable lipophilic skin moismrizmg agents for use herem are typically nonflowable at 95 °F at low stress Some examples of lipophilic skm moismrizmg agents which are suitable for use m the present invention include, petrolatum or petrolatum blends, microcrystallme waxes, polyalkenes, paraffins, sihcone gums, and mixture thereof, as well as blends of these materials with flowable materials Examples of lipophilic skm moismrizmg agents which are not suitable by themselves for use in the present invention mclude, sihcone oils and triglyceπde oils

The lipophilic skm moismrizmg agent used herem preferably has a Vaughan solubility Parameter (VSP) of from 5 to 10, preferably from 5.5 to 9, as defined by Vaughan in Cosmetics and Toiletries. Vol 103, p 47-69, October 1988

2 Aqueous Cleansing Phase

The emulsions employed m the personal cleansing bar compositions of the present invention also comprise an aqueous cleansing phase which comprises a lathering synthetic surfactant and water a The Lathermg Surfactant

The lathering synthetic surfactant is selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, amphoteπc surfactants, and mixtures thereof

The lathermg surfactant is defined herem as a surfactant or surfactant mixture thereof that when combined have an equilibrium surface tension of between 15 and 50 dynes/cm, more preferably between 25 and 40 dynes/cm as measured at the CMC (critical micelle concentration) at 25 °C Some surfactant mixes can have a surface tension lower than those of its individual components

The personal cleansing compositions herein comprise from about 0 5% to about 50%, preferably from about 5% to about 40%, and most preferably from about 10% to about 35% of a lathermg surfactant Anionic surfactants useful herein include: acyl isethionates, acyl sarcosinates, alkylglycerylether sulfonates, alkyl sulfates, alkyl sulfates, acyl lactylate, methylacyl taurates, paraffin sulfonates, linear alkyl benzene sulfonates, N-acyl glutamates, alkyl sulfosuccinates, alpha sulfo fatty acid esters, alkyl ether carboxylates, alkyl phosphate esters, ethoxylated alkyl phosphate esters,, alpha olefin sulphates, the alkyl ether sulfates (with 1 to 12 ethoxy groups) and mixtures thereof, wherein said surfactants contain C8 to C22 alkyl chains and wherein the counterion is selected from the group consisting of: Na, , NH4, N CH2CI_2θH 3. The anionic surfactant is more preferred when selected from the group consisting of acyl isethionate, acyl sarcosinates, acyl lactylates, alkyl sulfosuccinates, alkylglycerylether sulfonates, methylacyl taurates, alkyl ether sulfates, alkyl sulfates, alkyl phosphate esters and mixtures thereof, wherein said surfactants contain has C8 to C 14 alkyl chains and is present at a level of from about 8% to about 20%.

Amphoteric synthetic surfactants cannot serve as the sole surfactant in this product, but are preferred as a co-surfactant at a lower level of from about 1 % to about 10%, by weight and the more preferred types are selected from alkyl-ampho mono- and di-acetates, alkyl betaines, alkyl dimethyl amine oxides, alkyl sultaines, alkyl amidopropyl betaines, alkyl amidopropyl hydroxysultaines, and mixtures thereof, wherein said surfactants contain C8 to C22 alkyl chains.

Nonionic synthetic surfactant cannot serve as the sole surfactant in this product, but can be used as a co-surfactant at a lower level of from about 1 % to about 15% by weight. The more preferred types selected from the group consisting: alkyl glucose amides, alkyl glucose esters, polyoxyethylene amides, fatty alkane amides, alkyl amine oxides, alkyl polyglucosides, polyoxy ethylene alkyl phenols, polyoxyethylene esters of fatty acids, EO/PO block co-polymers such as polyoxamines and poloxamers, sorbitan esters and alcohol esters, and mixtures thereof.

Cationic synthetic surfactant cannot serve as the sole surfactant in this product, but are preferred as a co-surfactant at a lower level of from about 0.5% to about 6%, by weight. The more preferred types of cationic surfactants are selected from the group consisting: alkyl trimonium chloride and methosulfate, and dialkyldimonium chloride and methyl sulphate, and alkyl alkonium chloride and methyl sulphate and mixtures thereof. These surfactants contain C12 to C24 carbon atoms per alkyl chain. The most preferred cationic is selected from the group consisting of stearalkonium chloride, stearyltrimonium chloride, Di-stearyl-dimonium chloride, and mixtures thereof. Cationic surfactants may also act as a lipid deposition aid.

b. Water

The aqueous phase of the emulsion employed in the personal cleansing bar compositions of the present invention also comprises water as an essential component. The water is typically present at a level of from about 10% to about 50%, preferably from about 12% to about 45%, and most preferably from about 15% to about 35% of the personal cleansing compositions of the present invention. c. Optional Ingredients

The aqueous phase of the emulsion employed in the personal cleansing bar compositions of the present invention can also contain a number of optional ingredients.

A highly preferred optional component of the present compositions are one or more humectants and solutes. A variety of humectants and solutes can be employed and can be present at a level of from about 0.1 % to about 50 %, more preferably from about 0.5 % to about 35 %, and most preferably from about 2 % to about 20 %. of a non- volatile, organic material having a solubility of a least 5 pans in 10 pans water. A preferred water soluble, organic material is selected from the group consisting of a polyol of the structure:

Rl - 0(CH₂ - CR2HO)_nH

where Rl = H, C1-C4 alkyl; R2 = H, CH₃ and n = 1 - 200; C2-C10 alkane diols; guanidine; glycolic acid and glycolate salts (e.g. ammonium and quaternary alkyl ammonium); lactic acid and lactate salts (e.g. ammonium and quaternary alkyl ammonium); polyhydroxy alcohols such as sorbitol, glycerol, hexanetriol, propylene glycol, hexylene glycol and the like; polyethylene glycol; sugars and starches; sugar and starch derivatives (e.g. alkoxylated glucose); panthenol (including D-, L-, and the D, Informs); pyrrolidone carboxylic acid; hyaluronic acid; lactamide monoethanolamine; acetamide monoethanolamine; urea; and ethanol amines of the general structure (HOCI-2CH2) NHy where x = 1-3; y = 0-2, and x+y = 3, and mixtures thereof. The most preferred polyols are selected from the group consisting of glycerine, polyoxypropylene(l) glycerol and polyoxypropylene(3) glycerol, sorbitol, butylene glycol, propylene glycol, sucrose, urea and triethanol amine.

Oil thickening polymers, such as those listed in EP 0 547 897 A2 to Hewitt, published 23/06/93, incorporated herein by reference, can also be included in the bar compositions herein if the final rheology of lipid and polymer falls within the preferred range.

A preferred optional ingredient are one or more cationic and/or nonionic polymeric skin conditioning agents. A variety of polymers can be employed and can be present at a level of from about 0.1 % to about 10%, and more preferably 0.25% to about 3% of a polymeric, nonionic, cationic or hydrophobically modified polymeric skin feel aid, selected from the group consisting of cationic polysaccharides of the cationic guar gum class with molecular weights of 1,000 to 3,000,000, cationic and nonionic homopolymers derived from acrylic and/or methacrylic acid, cationic and nonionic cellulose resins; cationic copolymers of dimethyldialkylammonium chloride and acrylic acid; cationic homopolymers of dimethyldialkylammonium chloride; cationic polyalkylene and ethoxypolyalkylene imines; and mixes thereof. Examples are hydroxypropyl guar, guar hydroxypropyltrimonium chloride, polyquaternary 3, 5, 6, 7, 10, 11 and 24. In order to achieve the benefits described in this invention, the poly er must have characteristics, either structural or physical which allow it to be uιtabl> and fulh hydrated and subsequently well incorporated into the soap matrix

A variety of additional ingredients can be incorporated into the compositions of the present invention These materials including, but not limited to, bar appearance aids, salts and their hydrates clays, and other "filler materials" are listed in US Pat Application Serial No 07/782,956 to Kacher et al, incorporated herein by reference Examples of other suitable materials are disclosed in U S Patent No 4,919,934, to Deckner et al , issued April 24, 1990, which is incorporated herein by reference

Other non limiting examples of these additional ingredients include vitamins and derivatives thereof (e g , ascorbic acid, vitamin E, tocopheryl acetate, and the like), sunscreens, thickening agents (e g , polyol alkoxy ester, available as Crothix from Croda), preservatives for maintaining the ami microbial integrity of the compositions, anti-acne medicaments (resorcinol, salicylic acid, and the like), antioxidants, skin soothing and healing agents such as aloe vera extract, allantoin and the like, chelators and sequestrants, and agents suitable for aesthetic purposes such as fragrances, essential oils, skin sensates, pigments, pearlescent agents (e g , mica and titanium dioxide), lakes, colorings, and the like (e g , clove oil, menthol, camphor, eucalyptus oil, and eugenol)

B Rigid Semi-Continuous. Interlocking Open Mesh Crystalline Network

The personal cleansing bar compositions of the present invention also comprise from about 10% to about 50% , preferably from about 15% to about 35 %, most preferably from about 15% to about 25 % of a rigid, semi-continuous, interlocking open mesh crystalline network comprised of fatty acid soap The interlockmg mesh can impart strength to the three-dimensional structure, even in the presence of relatively high levels of lipid and water The open mesh structure contains substantial void^* areas which are filled by a two phase lipid and aqueous emulsion, preferably an oil in water emulsion

The crystalline network can comprise crystals in the form of either interlocking platelets and/or fibers, preferably fibers Preferably said fibers are comprised of alkyl metal soaps of fatty acids having alkyl cha lengths of 8 to 24, preferably 12 to 18, more preferably 12-14 carbon atoms The soap is preferably selected from sodium soap, magnesium soap and mixtures thereof Sodium soap is most preferred

II Process for Preparing Lathering and Moisturizing Personal Cleansing Compositions Containing

Nonspherical Lipophilic Skin Moisturizing Agent Particles

Personal cleansing bar compositions wherein at least about 10% by weight of the lipophilic skm moisturizing agent particles the bar lather are nonspherical are prepared by forming a soap stream, forming a separate lipid stream, and combining the two streams before passing the mixture through a static mixer After passing through the static mixer, the mixture is then poured into molds The process is described in detail as follows A soap stream is typically prepared in the crutcher by mixing fatty acid precursor and optionally polyol and then heating to a temperature ranging from about 150°F to about 180°F Salt, water and caustic solution are then typically added and the mixture is stirred at a slow speed until a smooth aqueous molten liquid is formed The temperature durmg neutralization of the molten liquid is increased to a temperature ranging from about 180°F to about 200 °F The temperature is then preferably maintained m the range of from about 180°F to about 200^:,F while the following gredients are added, preferably m the order given synthetic surfactant, preservatives (if any), whitemng aid (if any), sensory aids (if any), and perfume (if any)

Separately, a lipid stream containing the lipophilic sk moisturizing agent is prepared and heated to a temperature ranging from about 145°F to about 160° This hpid stream is injected mto the soap stream just pπor to the static mixer

The static mixer employed herem is a Koch Mixer, such as a Koch/Sulzer SMX Mixer, and can suitably employ from 2 to 8 elements, typically welded in pairs The number of elements selected within this range is dependent on the viscosity of the soap stream In general, the higher the viscosity of the soap stream, the fewer the number of elements which are suitably employed For example, if the viscosity of the soap stream is less than about 6,000 centipoise, the number of elements employed m the static mixer ranges from 4 to about 6 If the viscosity of the soap stream ranges from about 6,000 to about 10,000 centipoise, the number of elements employed in the static mixer ranges from about 2- to about 4 If the viscosity of the soap stream is greater than about 10,000 centipoise, the number of elements employed in the static mixer ranges from about 1 to about 2

The flow rate of the lipid and soap streams through the static mixer preferably ranges from about 500 grams/mmute to about 2000 grams/mmute, more preferably from about 700 grams/mmute to about 1500 grams/minute, and most preferably from about 1000 grams/mmute to about 1300 grams/minute Dimensionless shear (shear rate x residence time) in the static mixer is less than about 910

Upon exiting the static mixer, the soap/hpid mixture is cooled to room temperature, whereby the lipophilic skin moisturizing agent particles crystallize, maintaining their elongated (e g , nonspherical) shape The lipophilic skin moisturizing agent particles remain elongated in the bar lather The bars are typically removed from the molds and packaged Alternatively, the mold itself can serve as the package III Moisturizing and Lathermg Personal Cleansing Bar Compositions

The personal cleansing bar compositions of the present vention have a Lipid Deposition Value (LDV) of at least about 10 micrograms/square centimeter, preferably at least about 20 micrograms/ square centimeter, most preferably at least about 30 micrograms/square centimeter, as measured by the Deposition Method set forth hereinafter in the Analytical Methods Section Analvtical Methods

A number of parameters used to characterize elements of the present invention are quantified by particular experimental analytical procedures Each of these procedures are described in detail as follows 1 Deposition of the Lipophilic Skin Moismrizmg Agent

A Preparation

The arms are washed with a nonsoap-containing, πon pid-containing product to reduce background mterference as much as possible, then bloned dry The subject then wets the entire surface of the inner forearm with 95-100F tap water for five seconds The subject then saturates a puff, such as that described Campagnoh, U S Patent 5, 144,744, Issued September 8, 1992, and allows the puff to drain for 10 seconds One mil liter of the liquid personal cleansing composition which contains the lipophilic skin moismrizmg agent is applied to the forearm of the subject and then the product is rubbed with the puff for 10 seconds to generate lather The lather is allowed to remain on the forearm for fifteen seconds, followed by a thorough r se for fifteen seconds with the water flowing from inner elbow to wrist The subject arm is then pat dried with a paper towel The subject then allows the arm to "air" dry for 30 seconds

B Deposition Protocol- Sebumeter

Deposition of the lipophilic skin moisturizing agent on the skm is measured using a a Sebumeter SM810 which is commercially available from Courage and Khazaka GmbH The Sebumeter measures the amount of lipophilic skm moisturizing agent that has been deposited on the skm via photometry of a special plastic strip, which becomes transparent when it absorbs the lipophilic skm moisturizing agent The plastic strip is extended over a mirror which is connected to a sprmg The measuring head of the device (comprised of spring, mirror and plastic strip) is pressed against the skm for 30 seconds The Deposition Value (μg/sq cm) is indicative of the amount of lipophilic skm moisturizing agent on the sk , the Deposition Value increases with mcreased amount of lipophilic skm moisturizing agent The method is insensitive to humidity Sebumeter readmgs (3) are taken along the length of the forearm and the Deposition Value (μg/sq cm) is defined as the mean of the 3 readmgs, divided by a conversion factor to translate the sebumeter readmgs to actual deposition levels m μg/sq cm

The Sebumeter has the following limitations

1 The Sebumeter tape also detects natural skin lφids A criterion of this test is that subjects baseline value measured on the Sebumeter, prior to washmg, be less than or equal to 3 μg/sq cm of forearm skm 2 The Sebumeter like other surface extraction measurements may not measure all the deposited lipophilic sk moisturizmg agent, if the skm topography is undulating it is possible that deposited lipophilic skm moisturizing agent may not be extracted by the Sebumeter tape

3 The Sebumeter tape becomes saturated at a Deposition Value of above about 300 u g/sq cm, so this method can only measure deposition values up to about 300 μg/sq cm

4 Different lipophilic skm moisturizmg agents will have different conversion factors For testing non-petrolatum hpids, a new calibration curve is required

C Calibration

To translate the Sebumeter data obtained as hereinbefore described into deposition data, it is necessary to generate a conversion factor To generate the conversion factor, an extraction is done for each lipid system and the extracted sample is analyzed by gas chromotography The extraction is done at the same time as the Sebumeter reading and is taken from the same forearm the extraction procedure is as follows

1) An open-ended glass cylmder (2 inches in diameter) is placed onto the subject's inner forearm and securely strapped in place

2) Five ml of extraction solvent is added to the cylinder

3) The liquid is stirred on the subject's arm for 30 seconds usmg a blunt-ended glass stirring rod The full surface area of the enclosed forearm is treated with solvent

4) The liquid is transferred to a 6 dram vial using a disposable transfer pipet

5) Steps 2-5 are repeated two times (total of three samples, 15 ml of solvent collected) The extracted sample is then analyzed by gas chromotography as follows

APPARATUS

Gas Chromatograph HP 5890 or equivalent equipped with capillary inlet system and flame lonization detector Integration System PEN Turbochrom v4 0 data system, or HP 3396 Series II mtegrator, or equivalent with peak-grouping capability Column DB-5ht, 30 M x 0 32 mm I D , 0 10 μm film thickness, J&W Scientific cat no 123-5731 Analytical Balance Capable of weighting to 0 0001 g

Pipet 1 mL, Class A

Volumetric Flask 1000 mL, 100 mL, glass stoppered

Glass Syrmge 100 μL capacity

Autosampler Vials With crimp-top caps

Dry Bath Regulated at 80 - 85 °C

Pipettor Ependorf Repeator with 12 5 mL reservoir

Stir Plate and Stir Bars Teflin-coated stir bars

REAGENTS

Heptane ACS grade Squalane Aldπch cat no 23,431-1 or equivalent Lipid Standard

GC CONDITIONS

Carrier Gas Helium UHP grade or regular grade helium purified through a dry tube and an oxygen scrubber Flow pressure regulated at 25 psi with 25 ml/min split

Injection Mode Splitless Injection Volume 2 μl Injector Temperature 310°C Oven Temperature 100°C for 0 mmutes @ 10°C/mιn to 350°C, hold for 6 mm Program

Detector Temperature 350 °C Hydrogen and Air Flows Optimized for gas chromatograph used Bunching Factor 2

SOLUTIONS

Internal Standard Solution Into a clean, dry 100 mL volumetric flask, analytically weight 0 1 g of squalane, recording weight to nearest 0 0002 g Dilute to volume with heptane, stopper and stir to dissolve (A 1 1000 dilution of this solution can be used as the extraction solvent when generating samples )

Lipid Stock Solution Into a clean, dry 100 ml volumetric flask, analytically weight 0 5 gram of lipid standard, recordmg weight to nearest 0 0002 g Dilute to volume with heptane, stopper and stir to mix

Lipid Working Standards Label three autosampler vials as follows " 100 μg," "300 μg" and "500 μg " Using the glass syrmge, transfer 15 μL of internal standard solution mto each vial Rmse syrmge well with heptane, then use it to transfer the following amounts of lipid stock solution to the vials

Std Vol Stock Soln (uL)

100 μg 20 300 μg 60 500 μg 100

Dilute to approx 0 5 mL with heptane, then cap and shake

OPERATION

1 Calibration Run each standard under the above conditions Select the 10-14 largest peaks from the calibration run and create a peak group within the calibration of the method Assign the amount of lipid m the standard to die group for each calibration level Plot the area ratio on the y-axis Do not force the lme through the origin or include the origin The r2 value should be at least 0 9990 Check calibration every ten or twelve samples and at the end of the sample run 2 Sample Analysis Evaporate samples to dryness under a stream of dry nitrogen Reconstitute in 0 5 mL heptane Cap tightly and place on dry bath for 5 minutes shake to dissolve completely Transfer to autosampler vials and analyze on calibrated instrument with the proper ISTD amount entered Important Because the baselme is cluttered, manually check each result file for correct peak identification

The GC data is then plotted on a curve versus the Sebumeter data The slope of the curve is the conversion factor The conversion factor for petrolatum is 0 56

2 Determination of % Nonspherical Lipophilic Skm Moisturizing Agent Panicles

A stereo scope (Zeiss) is utilized to determine the weight % nonspherical particles the lather of the personal cleansing bar The personal cleansmg bar is lathered under warm tap water (95-100°F) a drop of concentrated lather is then applied to a microscope slide The slide is observed under bright field illumination at about 20x magnification The number of nonspherical particles is counted the weight % nonspherical particle is determined by dividing the number of nonspherical particles by the total number of panicles

3 Emulsion Stability Centifuge Test

The following test is used to determine the degree of stability of an emulsion which contains a moisturizing phase and an aqueous cleansmg phase

A ten percent (10%) solution of the bar composition is made by weighing 10 grams of the bar, finely chopped, to 120^CF city water The solution is stirred overnight (18 hours) usmg a magnetic stir plate and 1/2" stir bar

The stirred sample is then centπfuged for 150 minutes at 10,000 RPM and 25°C usmg a Beckman L8-80-R60 Ultracentrifuge with a SW-40 rotor If the emulsion is suitably unstable for use in the bars of the present invention, a lipid top layer is observed Emulsion which do not exhibit a top lipid layer are too stable for use herein

Examples

The following are nonlimitmg examples of the personal cleansing bar compositions of the present invention

Ingredients A B

Sodium Myπstic Soap (C14) 13 44 12 25

Sodium Laurie Soap (C12) 1 44 1 54

Coconut Soap 1 12 0 21

Free Fatty Acid 0 05 1 40

Alkyl Glyceryl Ether Sulfonate 2 5 19 90

Sodium Cocoyl Isethionate 22 0 4 08 Coco Betaine 0.44

Sodium Lauryl Sarcosinate 3.48

Sodium Lauryl Sulfosuccinate 1.19

Water 22.05 18.89

Dimethicone 2.0 1.0

Petrolatum 7.0 7.0

Soybean Oil 7.0 7.0

NaCl 1.66 1.79

Miscellaneous 21.74 20.83 (Soybean Oil and Petrolatum are premixed before addition through the static mixer)

%Nonspherical ( > 10 mm, by weight) > 50 > 50

Preparation of Examples:

Fatty acid (soap precursor) and solvents are mixed in the crutcher at 175 F. Sodium hydroxide, salt and water are then premixed, and added to the hot crutcher to produce the soap The additional ingredients, with the exception of the soybean oil and the petrolatum, are then added stepwise to crutcher until a smooth melt is formed. The crutcher material and the lipid are metered and combined into a stream and passed through a Koch/Sulzer SMX static mixer with a total flow rate of 1163 g/min at 165 F (1000 g/min soap flow, 163 g/min lipid). This stream then flows through 4 static mixing elements, welded in pairs. After flowing through the mixer, the soap is collected in molds and allowed to cool.

Claims

1. A pour- molded, lathering, skin cleansing bar composition characterized in that it comprises:

(a) an unstable emulsion comprising:

(i) a moisturizing phase comprising from 5% to 40% by weight of the bar composition of lipophilic skin moisturizing agent particles; and

(ii) a cleansing phase comprising from 1% to 50% by weight of the bar composition of a lathering synthetic surfactant and from 10% to 50% by weight of the bar composition of water; and

(b) from 10% to 50% of a rigid semi-continuous, interlocking open mesh crystalline network structure comprised of fatty acid soap; wherein said unstable emulsion is contained within interstices of said open mesh crystalline network, wherein at least 10% by weight of the lipophilic skin moisturizing agent particles having a diameter of greater than 10 microns in the personal cleansing bar lather are nonspherical; and wherein the personal cleansing bar composition is prepared by a process comprising the steps of:

1) forming a soap stream;

2) forming a separate lipid stream; 3)combining the soap stream and lipid stream;

4)passing the combined soap/lipid stream through a Koch static mixer; and 5) pouring the mixture into a mold.

2 The skin cleansing composition according to any one of the preceding claims which has a Lipid Deposition Value of at least 10 micrograms/square centimeter

3. The skin cleansing bar composition according to any one of the preceding claims wherein the fatty acid soap is selected from the group consisting of sodium soap, magnesium soap and mixtures thereof having alkyl chainlengths of from 8 to 24 carbon atoms.

4. The skin cleansing bar composition according to any one of the preceding claims wherein the lipophilic skin moisturizing agent particles are comprised of particles selected from the group consisting of petrolatum, silicone gum, and mixtures thereof.

5. The skin cleansing bar composition according to any one of the preceding claims wherein the soap stream is prepared by heating fatty acid to a temperature ranging from 65.5 to 82.2°C, adding salt, water and caustic until smooth, increasing temperature to within the range of from 82.2 to 93.3°C and then adding optional ingredients.

6. The skin cleansing bar composition according to any one of the preceding claims wherein the lipid stream is heated to a temperature ranging from 62.8 to 71.1 °C before it is combined with the soap phase.

7. The skin cleansing bar composition according to any one of the preceding claims wherein the static mixer contains from 2 to 8 elements.

8 The skin cleansing bar composition according to any one of the preceding claims wherein the flow rate of the soap/lipid mixture through the static mixer ranges from bout 500 grams/minute to 2000 grams/minute.

9 The skin cleansing bar composition according to any one of the preceding claims wherein the dimensionless shear in the static mixer is less than 910.

10. The skin cleansing composition according to any one of the preceding claims wherein at least 30% by weight of the lipophilic skin moisturizing agent particles having a diameter of greater than bout 10 microns in the bar lather are nonspherical.