WO1991016412A1

WO1991016412A1 - Mild soap-synbar with improved bar character and processability

Info

Publication number: WO1991016412A1
Application number: PCT/US1991/002201
Authority: WO
Inventors: James Charles Dunbar; Marcus Wayne Evans; Stephen Allen Mccoy; James Robert Schwartz
Original assignee: The Procter & Gamble Company
Priority date: 1990-04-25
Filing date: 1991-04-01
Publication date: 1991-10-31
Also published as: AU7779091A; NZ237937A

Abstract

This invention comprises a personal cleansing soap-synbar with improved mildness, bar character, and improved processability. The milder soap-synbar comprises 5 % to about 30 % of saturated long chain alkyl sulfate having alkyl chains of 16 and 18 carbon atoms.

Description

I

MILD SOAP-SYNBAR WITH IMPROVED BAR CHARACTER AND PROCESSABILITY

TECHNICAL FIELD This invention relates to cleansing soap bars containing some synthetic surfactant and to processes of making them.

BACKGROUND OF THE INVENTION

Personal cleansing with surface-active cleansing preparations has become a focus of great interest. Many people wash and scrub their skin with various surface-active preparations frequently. Ideal cleansers should be cost effective, cleanse gently and rinse well. Most toilet bars fall short in this respect.

The synthetic detergents which are sufficiently inexpensive to be considered for making bars and which have the requisite lather and cleansing power, are all far more soluble than the C12-C18 fatty soaps which are primarily used for bars. Further¬ more, none of the synthetic products as yet matches the low cost of soap when compared on a 100% active ingredient basis. Still another difficulty of the synthetics is that they do not feel like soap when used for bathing. The familiar subjective sensation of siipperiness is somewhat modified in the case of most synthetics, and it persists even after prolonged rinsing. Soap feels the same way in very soft water, but in water of average hardness the siipperiness is rapidly quenched, presumably by the formation of lime soaps. In spite of all these difficulties, several toilet bars based on synthetic detergents are currently being marketed. Their chief advantages lie in their ability to lather profusely in hard water and in the fact that they do not form scum or deposits of dirt on the basin or bathtub walls. The best synthetic bars now being marketed cost considerably more than toilet soap bars. The use of synthetic detergent surfactants in soap bars is well known, documented in U.S. Pat. Nos.: 2,988,511, Mills et al . , issued June 13-, 1961; 3,043,778, Kelly, issued July 10, 1962; and 3,598,746, Kaniecki et al . , issued Aug. 10, 1971, said patents being incorporated herein by reference.

Commonly assigned U.S. Pat. No. 4,820,447, Medcalf et al . , issued April, 1989, hereby incorporated herein by reference, discloses a mild soap bar comprising a polymeric skin mildness aid. A key mild synthetic surfactant used in synbars is alkyl glyceryl ether sulfonate. See U.S. Pat. Nos.: 2,988,511, su^pra: 2,989,547, Whyte, issued June 20, 1961; 2,999,068, Pilcher et al., issued Sept. 5, 1961; and 3,024,273, Whyte et al . , issued Mar. 6, 1962, all incorporated herein by reference.

U.S. Pat. No. 4,180,470, Tokosh et al., issued Dec. 25, 1979, discloses a method for making improved acyl isethionate detergent bars with from 2-6% of sodium alkoxy hydroxy propane sulfonate (a synonym for alkyl glyceryl ether sulfonate) with alkyl chains of from 8 to 22 carbon atoms in conjunction with a small amount of sodium chloride. Ci8 alkyl glyceryl ether sulfonate at 5% is used in an example. The added alkyl glyceryl ether sulfonate and salt are used to improve bar wear rate without adversely affecting its lathering characteristics. Major drawbacks of most soap and synthetic surfactant com¬ bination toilet bars are poor processability and/or poor bar hardness. As a class, alkyl sulfates are considered as rather harsh synthetic surfactants. It will be appreciated that mild¬ ness, processability, lather, and bar quality make surfactant selection a delicate balancing act for combination toilet bars. Thus, it will be appreciated that rather stringent requirements for milder soap/synbars limit the choice of surface-active agents and final formulations represent some degree of compromise. Mildness is often obtained at the expense of processability and bar quality. There is always a need for an improved soap/synbar with good mildness, good bar quality and good processability.

OBJECTS OF THE INVENTION This invention relates to skin cleansing soap/synbar bar com¬ positions which provide improved skin mildness. Therefore, one object of this invention is to provide a composition which exhibits improved skin mildness. Another object of the present invention is to provide milder soap/synbar which has improved processability and consume acceptable bar quality.

Other objects will become apparent from the detailed descrip tion below.

SUMMARY OF THE INVENTION This invention is an improved milled, mild personal cleansing soap-synthetic bar comprising: a mixture of soap and long chain alkyl sulfate surfactants having saturated C16-C18 alkyl chains for improved mildness and improved processability.

- DETAILED DESCRIPTION OF THE INVENTION Disclosed is a milled soap-synthetic bar comprising: (1) from about 5% to about 25%, preferably from about 10% to about 20%, of C16-C18 alkyl (chain) sulfates and (2) from about 30% to about 70%, preferably from about 35% to about 60% soap by weight of the soap bar. The ratio of the alkyl sulfates to soap is from about 1:1.5 to about 1:6, preferably from about 1:2 to about 1:4. The long chain alkyl sulfates are surprisingly and unexpectedly excellent or superior substitutes for the ultra mild synthetic surfactants alkyl glyceryl ether sulfonate and/or cocoyl isethio¬ nate in soap/synbar compositions. The long chain alkyl sulfates provide a surprisingly acceptable improvement in bar processa¬ bility, while not significantly impairing bar mildness or the desirable physical characteristics of the bars. The C16-C18 alkyl sulfates are derived from corresponding saturated straight chain alcohols. The Ciδ-Cis alkyl sulfates, as defined herein, comprise said Ciδ-Cis alkyl chains at a level of at least about 90%, preferably about 93%, and more preferably about 97%. In general, the ratio of Ci6 to C\Q can range from about 4:1 to about 1:4 by weight. A commercially available C16-C18 alkyl sulfate is SIPON^® EC-Ill (formerly SIPEX^® EC-Ill), sodium cetearyl sulfate, which is approximately 60% Ci6 and 36% Cχ8- SIPON^® EC-Ill is sold by Alcolac Company, Baltimore, MD 21226. Another source is Henkel Corp., Ambler, PA 19002. Henkel's sodium cetearyl sulfate, LANETTE' E, is an estimated 50-50% C16-C18 alkyl sulfate sold as an emulsifier. The terms "soap-synthetic bar," also "soap-synbar," as used herein mean that the bar has more soap than synthetic surfactant unless otherwise specified. The term "AS soap bar" means a soap bar containing alkyl sulfate surfactant. The term "long chain" means Ciδ and Cχ8, and mixtures thereof. The term "AGS soap bar" means a soap-synbar containing alkyl glyceryl ether sulfonate surfactant.

The percentages, ratios, and parts herein are on a total composition or surfactant weight basis, unless otherwise speci- fied. All levels and ranges herein are approximations unless otherwise specified.

It is noted that surfactant mildness can be measured by a skin barrier destruction test which is used to assess the irri- tancy potential of surfactants. In this test the milder the surfactant, the lesser the skin barrier is destroyed. Skin barrier destruction is measured by the relative amount of radio- labeled water (3H-H20) which passes from the test solution through the skin epidermis into the physiological buffer contained in the diffusate chamber. This test is described by T.J. Franz in the J. Invest. Dermatol .. 1975, 64, pp. 190-195; and in U.S. Pat. No. 4,673,525, Small et al . , issued June 16, 1987, incorporated herein by reference, and which disclose a mild alkyl glyceryl ether sulfonate (AGS) surfactant based synbar comprising a "standard" alkyl glyceryl ether sulfonate mixture. Barrier destruction testing surprisingly shows that the long chain alkyl sulfates are milder than standard AGS.

U.S. Pat. No. 4,820,447, Medcalf et al . , supra, discloses a mild soap bar comprising a polymeric skin mildness aid. The AS soap bars of this invention exhibit improved mildness over the soap bars disclosed in Medcalf et al . in the Modified Flex Test as disclosed herein. The improved AS soap bars also exhibit a processability improvement over comparable standard AGS soap bars. The AS bars are better in terms of bar firmness and smears.

The long chain alkyl sulfate comprises 5-30% by weight of the bars of this invention. Other soap bar ingredients are selected from: other surfactants, polymeric skin feel aids, moisturizers, fillers, etc. A preferred AS soap bar comprises: about 15-20% of cetearyl sulfate; 40-55%, soap; and about 1-44%, preferably 5-35%, moisturizer; about 0-8%, preferably 0.2-2%, polymeric skin feel aid; 10-50% fillers; and 4-20%, preferably 7-15%, water. To insure mildness and bar firmness, the synthetic detergent sur¬ factant system in the bars should contain the long chain alkyl sulfate.

However, limited amounts of other detergent surfactants can be used; particularly from about 2% to about 20%, preferably from about 3% to abut 15%, more preferably from about 4% to about 10%, of lather enhancing detergent co-surfactant, e.g., mild ones, e.g., sodium lauroyl sarcosinate. Numerous examples of other surfactants are disclosed in the patents incorporated herein by reference. They include limited amounts of other alkyl sulfates, anionic acyl sarcosinates, methyl acyl taurates, N-acyl gluta- ates, acyl isethionates, alkyl sulfosuccinates, alkyl phosphate esters, ethoxylated alkyl phosphate esters, trideceth _. sulfates, protein condensates, mixtures of ethoxylated alkyl sulfates and alkyl a ine oxides, betaines, sultaines, and mixtures thereof. Included in the surfactants are the alkyl ether sulfates with 1 to 12 ethoxy groups, especially ammonium and sodium lauryl ether sul- fates. Alkyl chains for these other surfactants are Cs-C 2_» preferably Cin-Cis- Alkyl glycosides and methyl glucose esters are preferred mild nonionics which may be mixed with other mild anionic or amphoteric surfactants in the compositions of this invention. The preferred cation in the AS salt is sodium. However, other cations such as triethanolammonium (TEA), ammonium, and K, etc., are also usable. As used herein the term "cationic polymer" includes naturally and synthetically derived cationic polymers. The abbreviation "CN" means coconut and "T" means tallow herein, unless otherwise specified. All percentages and proportions are by weight, unless otherwise specified.

The soap bar of this invention also comprises from about 30% to about 70% soap, preferably at least 25% of which is tallow soap. A preferred bar of this invention comprises 4/1 T/CN fatty acid soap mixture. The fatty acid soaps which are essentials of this invention are alkali metal soaps of fatty acids having alkyl chain lengths of C8-C2 _. preferably C12-C18, and especially those of the C10-C14 chain lengths which are important in producing lather rapidly and of good, highly acceptable quality. It is understood that coconut soap is interchangeable with palm kernel oil soap. The fatty acid soaps are present at a level of from 30-70%, and most preferably from 45-65%. A preferred soap has a ratio of tallow/coconut soap of from 1:1 to 9:1, preferably from 1:1 to 1.5:1.

A preferred AS soap bar also contains from about 2% to about 17% moisturizer, preferably one selected from glycerin and free fatty acid or mixtures thereof. A more preferred bar of this invention contains at least 4% moisturizer.

A preferred bar of this invention comprises about 0.1% to 5%, more preferably 0.2% to 2%, of a suitably fast hydrating cationic polymer. The polymers have molecular weights of from about 1000 to about 3,000,000. A preferred one is selected from cationic guar gums having a molecular weight range of 2,500-350,000.

The cationic polymer (skin conditioning agent) is selected from the group consisting of:

(I) cationic polysaccharides; (II) cationic copolymers of saccharides and synthetic cationic monomers, and (III) synthetic polymers selected from the group consisting of:

(A) cationic polyakylene imines (B) cationic ethoxy polyalkylene imines, and

(C) cationic poly[N-[-3-(dimethylammonio)propyl]-N'-[3- (ethyleneoxyethylene dimethylammoni0)propyl]urea dichloride]. The bar soap composition containing these relatively small amounts of polymer delivers significantly improved clinical mildness relative to a composition without the polymer. The resultant mildness approaches that of synthetic-based skin cleansing products. (It is known that certain synbars are gen¬ erally milder than those based on soap, particularly the lower chain length fatty acid soaps.) The mildness improvement is further demonstrated by an improved barrier function of the stratum corneum relative to a product without polyjner, as deter¬ mined by measurement of transepidermal water loss. The cationic polymers used in this invention also provide a desirable silky, soft, smooth in-use feeling. It is believed that the positively charged polymer combines with the negatively charged sites on the skin to provide a soft skin feel after use. Specific examples of members of the cationic polysaccaride class include the cationic hydroxyethyl cellulose JR 400 made by Union Carbide Corporation; the cationic starches Stalok^® 100, 200, 300 and 400 made by Staley, Inc.; the cationic galactomannans based on guar gum of the Galactasol 800 series by Henkel , Inc. and the Jaguar Series by Celahese Corporation.

Examples of members of the class of copolymers of saccharides and synthetic cationic monomers include those composed of cel¬ lulose derivatives (e.g. hydroxyethyl cellulose) and N,N-di- allyl ,N-N-dialkyl ammonium chloride available from National Starch Corporation under the trade name Celquat.

The cationic synthetic polymers useful in the present in¬ vention are cationic polyalkylene imines, ethoxypolyalklene imines, and poly[N-[-3-(dimethylammonio)propyl]-N'-[3-(ethylene- oxyethylene dimethylammonio)propyl]urea dichloride] the latter of which is available from Miranol Chemical Company, Inc. under the trademark of Miranol A-15, CAS Reg. No. 68555-36-2.

Preferred cationic polymeric skin conditioning agents of the present invention are those cationic polysaccharides of the cationic guar gum class with molecular weights of 1,000 to 3,000,000. More preferred molecular weights are from 2,500 to

350,000. These polymers have a polysaccharide backbone comprised of galactomannan units and a degree of cationic substitution ranging from about 0.04 per anhydroglucose unit to about 0.80 per anhydroglucose unit with the substituent cationic group being the adduct of 2,3-epoxypropyltrimethyl ammonium chloride to the natural polysaccharide backbone. Examples are JAGUAR C-14-S, C-15 and C-17 sold by Celanese Corporation. In order to achieve the benefits described in this invention, the polymer must have characteristics, either structural or physical which allow it to be suitably and fully hydrated and subsequently well incorporated into the soap matrix. Other ingredients of the present invention are selected for the various applications. E.g., perfumes can be used in formu¬ lating the skin cleansing products, generally at a level of from about 0.1% to about 1.5% of the composition. Alcohols, hydro- 5 tropes, colorants, and fillers such as talc and clay, can also be used. Cetearyl alcohol is a mixture of cetyl and stearyl alco¬ hols. Preservatives, e.g., sodium ethylenediaminetetraacetate (EDTA), generally at a level of less than 1% of the composition, can be incorporated in the cleansing products to prevent color and 10 odor degradation. Antibacterials can also be incorporated, usually at levels up to 1.5%. The following patents disclose or refer to such ingredients and formulations which can be used in the soap/synbars of this invention, and are incorporated herein by reference: 15 Pat. No. Issue Date Inventor(s)

4,234,464 11/1980 Morshauser 4,061,602 12/1977 Oberstar et al . 4,472,297 9/1984 Bolich et al . 4,491,539 1/1985 Hoskins et al . 20 4,540,507 9/1985 Grollier

4,673,525 6/1987 Small et al . 4,704,224 11/1987 Saud 4,812,253 3/1989 Small et al . 4,820,447 4/1989 Medcalf et al .

25

Laboratory Assessment of Bar The following test procedures are used to evaluate the critical bar performance attributes of smear (character) and bar firmness (processability) during use. 30 Bar Soao Firmness Test (Processability)

Equipment

1. Precision Scientific Co. Penetrometer with cone shaft.

2. 200 gram weight. Operation

35 1. Check that penetrometer is level.

2. Zero the dial indicator by squeezing the clutch trigger and >-. - 'pulling up on the depth^auge until'¹ it stops. ^*_Jf the ind.-d*.. cator does not reach zero, adjust with zero setting screw. 3. Place 200 gram weight on the shaft of the cone. Place the test product onto the shelf of the penetrometer. Put weigh¬ ing paper on top of the test product (this will give you a better measure of the penetrometer cone touching the product). By means of the coarse adjustment screw, bring the cone down until its point just touches the surface of the sample and the weighing paper can be easily removed. At this time, remove the weighing paper. Do not scrape or disturb the surface of the sample. 4. Release the cone by squeezing the clutch trigger. Allow the cone to settle for exactly 10 seconds before releasing the clutch trigger. 5. Push the depth gauge down until it stops. Read the dial. The reading is the penetration in tenths of a millimeter. Take three readings per test sample and take the average of the three readings. Divide this number by 10 and report data in millimeters. The smaller the penetrometer reading, the harder the prototype.

Bar Character Smear Tests 5 ml and Soap Dish Smear Test

Equipment

"Alathon" soap dishes Small measuring cylinder Method 1. Wet soap bar to be tested by dipping surface to be soaked in distilled water and shaking off excess water. This procedure leads to more uniform bar smear.

2. Place bar centrally on "Alathon" dish containing 5 ml of distilled water. Rock dish to break water tension. The Alathon dish was selected as being a standard, readily available (in U.S.) dish with low ridges.

3. Store overnight (approximately 18 hours) in standard con¬ ditions of temperature and humidity (27^βC/80^βF/80% RH were used). As this test measures the bar's ability to recover as well as absorb water, standard conditions avoid seasonal variations which may occur in uncontrolled laboratory over¬ night conditions. 4. Next morning, remove bar with a careful vertical lift and invert for judging. Judging

Bar Smear - Each judge grades soap bar smear by fingering the bar and taking into account both types of smear and amount of smear.

Wet Soap Dish - Similarly, each judge grades any residue remaining in the dish.

Grade Smear Description 10 Excellent

9 Very good smear 8 Good smear (Target) 7 Slightly poorer than desired 6 Marginal but still acceptable 5 Minimum acceptable smear 4 Poor and unacceptable 3 Very poor smear 2 Poorest normally seen 1 Extremely poor smear

100 ml Smear Test Principle

A bar of soap is soaked in distilled water for 16 hours. At that time a depression is made in the soaked surface. The degree of "fill-in" of the depression is a measure of "in-use" customer concern. Scope

This method is applicable to all bar soaps. Reagents Water - distilled 75^βF ± 5^βF Apparatus

Petri Dishes - 100 mm inside diameter x 22 mm high, bottoms only. Fisher 8-748D or equivalent.

Soap Perch - Plastic elliptical shape, 83 mm x 50 mm with approximately 5 mm prongs on each side. Local drug or variety store. Operation

Place soap perch in Petri dish. Fill dish with 100 ml 75°F ± 5°F water. Place bar on top of soap perch with logo side out of the water. Allow bar to soak for 16 ± 2 hours. Remove bar and place on the lab bench with the dry, logo side down.

Push a finger into the wet surface in approximately the middle of the bar. Observe the indentation in the bar and also the amount of material present in/on the water. Grading and Reporting Report according to the following description:

Good - Soaked surface maintains original bar shape, inden¬ tation remains after finger is removed, raised portion around indentation remains higher than bar surface. Poor - Shape of the soaked surface is deformed, surface is creamy-slimy, some of the soaked surface may run down side of bar, indentation partly fills or completely fills after finger is removed. The water may contain some soap residue. Grading Scale - Same as 5 ml . and Soap Dish Smear Test.

Clinical Assessment of the Toilet Bars The clinical test procedure used to evaluate several toilet bar formulations for skin mildness is given below.

Mildness Forearm Wash Test Procedure

The washings are performed by a technician. Each panelist is assigned a set of 8 products for washings, 4 per arm. The test procedure for each arm is: Protocol 1. Place 3M Micropore surgical tape with 4 precut 3.2 cm diameter holes on the volar forearm. Center tape on the lower inner forearm trying to keep the lower treatment area away from the wrist area. 2. Wet the forearm with warm (35-40°C) water. 3. Wet a nonwoven paper towel (Masslinn Towel, Chicopee Mills, New Brunswick, New Jersey) with warm water. Rub the 'towel, on the appropriate test product using a circular motion for .6 seconds. 4. Rotate the towel at each test site for 10 seconds.

5. Allow lather from the test products to remain on the test site for 90 seconds.

6. Rinse each site with warm water (35-40^βC) for 15 seconds.

7. Pat area dry with soft, disposable (BOUNTY^®) paper towel .

8. Wait 2 minutes and repeat above procedure for a second time. 9. This procedure is to be followed 2 times daily, for 4 consecutive days, and 1 time the final day of the study, for a total of 18 washings. Each of the daily visits will be approximately 3 hours apart. A visual inspec¬ tion of each test site is to be made just prior to the second wash procedure of the third day and 3 hours after the final wash of the fifth day. Observable dryness and erythema will be scored at each examination period. 10. The following grading scales are used:

Clinical Test Skin Grading Scales

The forearm skin grading scales reported herein are set out below.

Forearm Grading Scale - Skin Dryness 0 Perfect skin. 1.0 Patches of checking and/or slight powderiness and occasional patches of small scales may be seen. Distribution generalized. 2.0 Generalized slight powderiness. Early cracking or occasional small lifting scales may be present. 3.0 Generalized moderate powderiness and/or moderate cracking and lifting scales. 4.0 Generalized heavy powderiness and/or heavy cracking and lifting scales. 5.0 Generalized high cracking and lifting scales. Eczematous change may be present. Powderiness may be present but not prominent. May see bleeding crack. 6.0 Generalized severe cracking. Eczematous change may be present. Bleeding cracks may be present. Scales large, may be beginning to disappear.

Forearm Grading Scales - Skin Erythema

0 No redness 1.0 Barely detectable redness 2.0 Slight redness 3.0 Moderate redness 4.0 Heavy or substantial redness

5.0. Severe redness 6.0 Extreme redness The term "generalized" as used herein means that more than 50% of the surface area of the forearm exhibits the attribute. Whole unit skin grades reflect generalized condition. Half units are used to represent intermediate conditions.

Modified Flex Test Wash

Protocol 1. Wet one sponge under warm, about 37°C (95-100^βF) water until completely wet.

2. Squeeze the sponge 3-4 times to remove excess water.

3. Lather the moistened sponge, in a circular motion, directly on the test bar for 10 seconds. 4. Wash the appropriate test areas of the inner volar forearm for 60 seconds (i.e., washing motions of 2-3 circular revolutions per second). 5. Thoroughly rinse the wash area and pat dry with a paper towel (15-second rinse recommended). 6. This procedure is to be followed 3 times daily for 4 consecutive days and 2 times the final day of the study, for a total of 14 washings. Each of the daily wash procedures will be approximately 2 hours apart. A visual inspection of each test site is to be made just prior to the next wash procedure. Observable erythema will be scored at each examination period. The final examination is to be made about 2 hours following the 14th wash procedure. 7. The following erythema scoring scale is to be used:

0 = no evidence of erythema

1 = slight erythema (spotty and/or minimally 5 perceptible)

2 = moderate erythema (more uniform, pink-red)

3 = marked erythema (uniform, relatively brighter or deeper red)

10 Intermediate 0.5, 1.5, 2.5, and 3.5 increments may also be scored with necessary.

8. Arms are no longer subjected to the washing procedure if a rating of "2" or greater is attained. The score of

15 "2" is assigned for the remainder of the study.

9. Products are statistically compared by examining the^' number of Grade 2 or higher ratings. The fewer the number of these ratings, the milder the product is judged to be.

20 EXAMPLES

The following examples are illustrative and are not intended to limit the scope of the invention(s) . The detailed methods of making milled bars is well known. All levels and ranges, tem¬ peratures, results etc., used herein are approximations unless

25 otherwise specified.

The formulations of the products tested clinically are given in Tables 1 and 2. Table 1 is an estimated formulation of Lever 2000^®, a soap/synbar used as a standard control bar for the Flex Test. Comparative Example 1 is a commercially available soap bar

,30 used as a standard control for the Forearm Wash Test. Example 2 is a commercially available soap/synbar made with cationic poly¬ mers and 8.8% AGS. Example 3 is an experimental soap/synbar made with polymer and 23% AGS. Example 4 is the AS bar of this invention containing 18.25% cetearyl sulfate.

35

(Wt.%)

TABLE 2 (Continued) Test Example Formulas and Test Results (Wt.%) Triclocarban 1.5

Fragrance 1.32

Titanium Dioxide 0.80 Preservative 0.05

Water 11.0

Equal Equal

More More

5.5 7.5 6.5 8.0

6.0 6.5

Penetrometer (mm) 1.9 3.4 6.6 4.6

COMPARATIVE EXAMPLE 1

Comparative Example 1 is the control bar for the Forearm Wash Test. Note that Example 1 is less mild in the Modified Flex Test vs. the control bar for the Flex Test.

COMPARATIVE EXAMPLE 2

Comparative Example 2 is a standard soap/synbar formula with 8.8 parts synthetic sodium cocoglyceryl ether sulfonate (AGS) and 1.9% polymers. Example 2 is not as mild as the control bar in the Flex Test; but is milder than Example 1 in the Forearm Wash Test. EXPERIMENTAL COMPARATIVE EXAMPLE 3

This Example contains about 23% AGS and about 1.85% polymer. Note that this bar equals the control bar in the Modified Flex Test and is milder than the control bar in the Forearm Wash Test, but is too soft and is poor in smears, as shown in Tables 2 and 3. This bar is difficult to process on conventional soap bar making equipment. EXAMPLE 4 Example 4 of the present invention is equal the control bar for the Modified Flex Test. Example 4 is milder than Example 1, the control bar, in the Forearm Wash Test. Example 4 is harder than the mild experimental bar, Example 3, and is better than Example 3 and the Flex Test control bar in smears. Example 4 is easier to process than Example 3 because of its hardness. Example 4 is unexpectedly as mild as the control bar for the Flex Test. Example 4 is also as mild as the mild AGS-based experimental bar. Example 3 in both tests.

Although the control bar for the Flex Test is a harder bar than Example 4 and lathers well, Example 4 is, respectively, equal to and superior to the Flex Test control bar in mildness and smears. The key difference is in their surfactant systems. The formulation differences between Examples 3 and 4 in levels of water, fatty acids, glycerin, sarcosinate, salt and polymer are considered as negligible factors relative to the presence of AS for mildness, smears and hardness. The mildness values for Experimental Example 3 and Example 4 are about equal. The improvement in smears and penetrometer values for Example 4 over Example 3 results from the presence of alkyl (cetearyl) sulfate. The lower penetrometer value translates into improved processability for Example 4 over Example 3.

TABLE 3

Example Formulas 5 and 6 and Test Results (Wt.%)

TABLE 3 (Continued)

Example Formulas 5 and 6 and Test Results (Wt.%) Salt (Sodium Chloride/ Sodium Sulfate) 2.50 2.50

Triclocarban 0.25 0.25

Fragrance 1.20 1.20

Titanium Dioxide 0.55 0.55

Preservative 0.05 0.05 Water 13.00 13.00

While Example 4 is the present best mode of this invention,

Examples 5 and 6 are also improved soap/synbars of this invention.

Example 5 is better than Example 6 in smears and penetrometer (firmness). Example 5's lower penetrometer value indicates that it is easier to process than Example 6.

WHAT IS CLAIMED IS:

Claims

CLAIMS :

1. A milled personal cleansing soap-synthetic bar comprising: from about 5% to about 25% of saturated long chain alkyl sulfate surfactant and from about 30% to about 65% soap, wherein said saturated long chain alkyl sulfate surfactant has saturated alkyl chains of from about 16 to about 18 carbon atoms; and wherein the ratio of said alkyl sulfate to said soap is from about 1:6 to about 1:1.5.

2. The milled soap-synthetic bar of Claim 1 wherein said soap- synthetic bar contains from about 10% to about 20% of said long chain alkyl sulfate surfactant and from about 45% to about 55% of said soap and from about 4% to about 20% water.

3. The milled soap-synthetic bar of Claim 1 or 2 wherein said soap-synthetic bar contains said long chain alkyl sulfate and soap at a ratio of from about 1:2 to about 1:4.

4. The milled soap-synthetic bar of Claim 1 or 3 wherein said soap-synthetic bar contains other components selected from: moisturizers, colorants, solvents, fillers, other surfactants, polymeric skin feel and mildness aids, perfumes, and preserva¬ tives.

5. The milled soap-synthetic bar of Claim 1 or 4 wherein said soap-synthetic bar contains from about 40% to about 55% of said soap and 15% to 20% of said long chain alkyl sulfate surfactant mixture; from about 0% to about 40% moisturizer; from about 0% to about 50% fillers; from 0% to about 8% polymeric skin feel aid; and from about 7% to about 15% water, by weight of the bar.

6. The milled soap-synthetic bar of Claim 1 or 5 wherein said soap-synthetic bar contains said Ci6 and Cis alkyl chains having a ratio of from about 4:1 to about 1:4.

7. The milled soap-synthetic bar of Claim 1 or 6 wherein said alkyl sulfate is at least 90% C e and Cis-

8. The milled soap-synthetic bar of Claim 1 or 7 wherein said alkyl sulfate is at least 97% C\ζ and Cig.

9. The milled soap-synthetic bar of Claim 1 or 8 wherein said soap-synthetic bar has a bar hardness of less than about 6.0.

10. The milled soap-synthetic bar of Claim 1 or 9 wherein said soap-synthetic bar has smears of at least about 6 and wherein said bar has a lather enhancing detergent co-surfactant at a level of from about 2% to about 20% by weight of the bar composition.