WO1992016610A1

WO1992016610A1 - Mild personal cleansing bars with improved processability

Info

Publication number: WO1992016610A1
Application number: PCT/US1992/000802
Authority: WO
Inventors: Wayne Ellis Eccard; James Robert Schwartz; Theresa Anne Bakken; Lawrence Allen Gilbert
Original assignee: The Procter & Gamble Company
Priority date: 1991-03-21
Filing date: 1992-01-31
Publication date: 1992-10-01
Also published as: CA2105086A1; BR9205789A; IE920906A1; HU9302648D0; NO933301D0; EP0646169A1; CZ196493A3; SK101493A3; AU1877192A; FI934108A; HUT65146A; AR244797A1; NO933301L; JPH06506260A; FI934108A0; CN1065483A; MX9201237A; MA22472A1; PT100276A

Abstract

This invention is an improved mild personal cleansing syndet bar comprising: long chain alkyl sulfate having essentially saturated C15-C22, preferably C16-C18, alkyl chains, more preferably cetearyl sulfate, a high lathering, mild synthetic surfactants comprising C12-C14 alkyl isethionate, soap, fatty acids, and paraffin wax, preferably a high melting point paraffin wax. The bar has good processability, improved smears, and good in-use properties without meaningful lather negatives.

Description

MILD PERSONAL CLEANSING BARS WITH IMPROVED PROCESSABILITY

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of U.S. Pat. Appln. Ser. No. 07/674,282, filed March 21, 1991.

TECHNICAL FIELD This invention relates to personal cleansing bars based on synthetic surfactants and to processes of making them.

BACKGROUND OF THE INVENTION "Soap, since its appearance in history, has helped safeguard two of our greatest treasures: our health and our children. Health is directly related to cleanliness. Data proves that the higher the consumption of soap in a country, the lower will be the infant mortality rate. "In industrialized countries, soap is the most-taken-for- granted and readily available personal care product used on our body daily. Soap is also the most inexpensive product we use in relation to its per use cost. In many less fortunate countries both laundry and toilet soaps are still scarce, expensive essentials. . . .

"Soap is most probably the oldest of toiletries, and, in spite of being readily available in most parts of the world, it is still scarce in many countries. The oldest literary reference to soap relates to the washing of wool and is found in clay Sumerian tablets dating about 2500 B.C.E. Sumerian was a language spoken in the area of the Tigris and Euphrates rivers, now Southern Iraq. The patriarch Abraham and his family came from Sumer. Another Sumerian tablet, dating 2200 B.C.E. gives the formula consisting of water, alkali and cassia oil. "Cleanliness is essential to our well being. A clean body, clean bath, clean home, and clean environment are the norm today." (Soap Technology for the 1990's, L. Spitz et al . , American Oil Chemists' Society, Champaign, Illinois, pp. 1-2) This reference discusses syndet and combo bars, particularly on pp. 209-229.

Synthetic surfactant-based personal cleansing bars have attracted much interest recently because they can be selected to 5 be milder to the skin than soap-based products. This mildness, however, comes with negatives to both the manufacturer and the consumer. The bar soap manufacturer experiences difficult processability due to the sticky nature of such products, as well as high raw material costs. The consumer experiences the negative ° performance properties of poor lather, messy smear, bar softness, and, consequently, high wear rates.

The use of paraffin wax in synthetic surfactant-based bars, per se, is known. However, the known bars suffer from a combi¬ nation of harshness and/or lather deficiencies. E.g., U.S. Pat. ⁵ No. 2,653,913, van Dijck et al . , issued Sept. 29, 1953, discloses bars comprising 80% synthetic anionic surfactant (selected from sodium secondary or primary alkyl sulfates or sodium dodecyl- benzene sulfonate), 18% paraffin, melting point (M.P.) 140-150'F, and 2% sodium alginate. The surfactants employed are non-mild ° surfactants.

U.S. Pat. No. 2,734,870, Lewis, issued Feb. 14, 1956, discloses bars comprising 40-60% paraffin (M.P. >125'F), 2-5% fatty acid, and 60-40% sodium alkyl aryl sulfonate. The high level of paraffin in these bars results in unacceptably low lather.

U.S. Pat. No. 3,129,187, Meehan, issued Apr. 14, 1964, discloses bars comprising 50-75% sodium alkylbenzene sulfonate,

5-35% stearyl alcohol, 1-25% paraffin (M.P. 125-170^βF), and 2-25% stearyl MEA. The harsh surfactants employed would result in harsh products.

U.S. Pat. No. 4,151,105, 0'Roark, issued Apr. 24, 1979, discloses bars comprising 20-40% synthetic anionic surfactant (composed of sodium cocoyl isethionate and/or sodium lauryl sulfoacetate), 10-30% paraffin (M.P. 130-140^βF), 5-15% powdered starch, 10-30% dextrin and 5% fatty acid. The low melting point of the wax employed would cause a substantial soil load on the lather potential and result in poor lather volumes. U.S. Pat. No. 4,335,025, Barker et al . , issued June 15, 1982, discloses a process for making syndet bars containing a "waxy extender."

OBJECTS OF THE INVENTION One object of this invention is to provide a personal cleans¬ ing syndet bar composition which exhibits improved lather and reduced bar messiness, while not sacrificing the processability of the syndet bar.

SUMMARY OF THE INVENTION This invention relates to an improved processable, mild personal cleansing syndet bar comprising: at least about 10% by weight long chain C15-C 2 alkyl sulfate having essentially satu¬ rated, preferably Ci6-Cj8, alkyl chains, soap, free fatty acid, a lathering mild surfactant comprising C12-C14 alkyl isethionate, and a selected paraffin wax. The bar has improved bar messiness without a meaningful lather negative.

DETAILED DESCRIPTION OF THE INVENTION A mild synthetic surfactant-based (syndet) bar with improved processability, good lather and/or reduced messiness (smear) is indeed an advance in this art. The present invention provides such an improved syndet bar comprising: (1) from about 10% to about 40%, preferably from about 15% to about 35%, of Ci5-C22_> preferably C15-C18, essentially saturated long chain alkyl sul- fates; (2) from about 15% to about 40%, preferably from about 18% to about 35%, of mild, high lathering, synthetic surfactants with at least about 10% by weight of the bar being C12-C1 alkyl isethionate; (3) from about 8% to about 25%, preferably from about 10% to about 20%, of Cχo-C22» preferably C12-C18, essentially saturated fatty acids; (4) from about 2% to about 15%, preferably from about 3% to about 12%, Cιo-C22_> preferably C12-C18, alkali metal soaps, preferably sodium or potassium soaps; (5) from about 10% to about 40%, preferably from about 13% to about 35%, paraffin wax with an average melting point of from about 130'F to about 180^βF, preferably from about 140^*F to about 165^*F, more preferably from about 142'F to about 160^*F; (6) from 0% to about 10% auxiliary plastic binders such as polyethylene glycols and/or monoglyceride; and (7) from about 1.5% to about 10%, preferably from about 2% to about 8%, more preferably from about 2% to about 5%, water.

While not being bound to any theory, it is advantageous to think of a synbar as comprising two separate components: the matrix and the actives. The matrix provides the physical charac¬ teristics (processability and bar messiness) while the actives provide lathering and mild properties. The matrix, if not chosen correctly, can impede lather generation, cause poor bar feel, increase or decrease wear rate beyond an acceptable level, and/or reduce product mildness. Likewise, the actives must be chosen so as to provide acceptable levels of lathering without negatively impacting mildness, a trade-off in formulations.

Bars with improved processability comprising long chain alkyl sulfate and selected binders are described in commonly assigned, copending U.S. Patent Applications: Ser. No. 07/605,614, J.R. Schwartz, W.E. Eccard, T.A. Bakken, and L.A. Gilbert, filed Oct. 30, 1990; and Ser. No. 07/647,030, J.R. Schwartz, W.E. Eccard, T.A. Bakken, and L.A. Gilbert, filed Jan. 28, 1991, incorporated herein by reference. The present compositions yield bars having even better product performance in the areas of lather and/or bar messiness than those specifically exemplified in those patent applications.

It will be appreciated that the development of an appropriate bar matrix is a delicate balancing act between plasticity and brittleness while not compromising lather performance. Typical bar matrix plasticizer materials such as triglycerides, fatty alcohols, etc., which tend to form a sufficiently plastic matrix, but also tend to depress lather potential. Other commonly used additive matrix materials such as salts, polysaccharides, etc., tend to make an overly brittle and water-soluble matrix that induces poor bar messiness performance.

The terms "synthetic bar," also "syndet bar," as used herein mean that the "bar" has more synthetic surfactant than soap unless otherwise specified. The term "AS syndet bar" means a syndet bar containing alkyl sulfate surfactant or its equivalent, unless otherwise specified. The term "long chain" means C15 and C22_> preferably Ci6-C20_> and mixtures thereof. The terms "C12-C14 alkyl" and cocoyl" as used herein are synonymous.

The percentages, ratios, and parts herein are on a total composition weight basis, unless otherwise specified. All levels and ranges herein are approximations unless otherwise specified. An essential element of the present invention is the surfac¬ tant system. The long chain alkyl sulfate (hereinafter including its long chain equivalent synthetic surfactants) is key and is defined herein, as comprising Ci6-Cj8 alkyl chains at a level of at least about 90%, preferably about 93%, and more preferably about 97%. The long chain alkyl sulfate (and its equivalents) is derived from corresponding saturated straight chain alcohols. The preferred alkyl sulfate has a ratio of Cjδ- is alkyl chains in the range of from about 100% Cie to about 100% Cis by weight. A commercially available Ciδ-Cis alkyl sulfate is SIPON^® EC-Ill (formerly SIPEX^® EC-Ill), sodium cetearyl sulfate, which is approximately 60% Ci6 and 36% Cis- 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% Ciβ-Cis alkyl sulfate sold as an emulsifier.

Other long chain surfactants which are equivalents to the long chain alkyl sulfate (mostly insoluble) could serve as either full or partial replacements for the long chain alkyl sulfate. Examples include long chain isethionates, sarcosinates, glyceryl ether sulfonates, etc. The acyl esters of isethionic acid salts, with esters of Ciδ-Cis acyl isethionates and no more than 25% or lower C1 acyl groups are also useful. Preferred is stearoyl isethioniate with C143%; Cjδ 50%; and Cis 47%.

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-H2θ) 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. The long chain alkyl sulfate preferably comprises 15-40% by weight of the bars of this invention.

The present invention contains a mild lathering surfactant at a level of from about 15% to about 40%, preferably from about 18% to about 35%_ Examples of a high lathering or lather enhancing surfactant, especially milder ones, are: C12-C14 alkyl isethio¬ nate; sodium lauroyl sarcosinate, C12-C14 alkyl glyceryl ether sulfonate. A "high lathering surfactant" as defined herein, is one which lathers better than the long chain Ciδ-Cis alkyl sulfate. A "mild surfactant" as defined herein is one that is milder than sodium dodecyl sulfate.

Numerous examples of surfactants in general are disclosed in the patents incorporated herein by reference. They include limited amounts of anionic acyl sarcosinates, methyl acyl taur- ates, N-acyl glutamates, acyl isethionates, alkyl sulfosuccinates, alkyl phosphate esters, ethoxylated alkyl phosphate esters, tride- ceth sulfates, protein condensates, mixtures of ethoxylated alkyl sulfates and alkyl amine 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 sulfates. Alkyl chains for these other surfactants are

C8"C22_> preferably Cio-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 bars of this invention can have up to about 10% of high lathering, non-mild or shorter chain or traditional (coconut) alkyl sulfates and still maintain the mildness requirement of the bar. A preferred syndet bar contains a mixture of C12-C1 alkyl isethionate (SCI) and sodium lauroyl sarcosinate in a ratio of from about 1:1 to about 3:1, preferably from about 1.5:1 to about 2.5 : 1 .

The primary plastic binders of the present invention are: (1) free fatty acid and (2) paraffin wax.

The fatty acid material which is desirably incorporated into the present invention includes material ranging in hydrocarbon chain length of from abut 10 to about 22, essentially saturated. These fatty acids may be highly purified individual chain lengths and/or crude mixtures such as those derived from fats and oils. The preferred composition is lauric and stearic acids in a ratio of from about 1:3 to about 3:1, more preferably from about 1:2 to about 2.5:1.

The composition may include soaps derived from hydrocarbon chain lengths of from about 10 to about 22, essentially saturated. It is preferred that the soap be the sodium salt, but other soluble soap can be used. Potassium, ammonium, triethanolammo¬ nium, and mixtures thereof, are deemed acceptable. The soaps are preferably prepared by the in situ saponification of the corres¬ ponding fatty acids, but they may also be introduced as preformed soaps. "Insoluble" soaps, e.g., magnesium and zinc soaps, are not included in the 2-15% level of "soap" in the composition defi¬ nition. However, insoluble soaps can be used as non-lathering, non-soil-load diluents.

An important component of this invention is a wax having a melting point (M.P.) of from about 130'F to about 180'F (54'- 82'C), preferably from about 140'F to about 165'F (60'-74'C), and most preferably from about 142'F to about 160'F (6r-71'C). A preferred paraffin wax is a fully refined petroleum wax which is odorless and tasteless and meets FDA requirements for use as coatings for food and food packages. Such paraffins are readily available commercially. A

suitable paraffin can be obtained, for example, from The National Wax Co. under the trade name 6975.

The paraffin preferably is present in the bar in an amount ranging from about 10% to about 40% by weight. The paraffin ingredient is used in the product to impart skin mildness, plas¬ ticity, firmness, and processability. It also provides a glossy look and smooth feel to the bar. The paraffin ingredient is optionally supplemented by a microcrystalline wax. A suitable microcrystalline wax has a melting point ranging, for example, from about 140'F (60^*C) to about 185'F (85'C), preferably from about 145'F (62'C) to about 175"F (79'C). The wax preferably should meet the FDA requirements for food grade microcrystalline waxes. A very suitable micro¬ crystalline wax is obtained from Witco Chemical Company under the trade name Multiwax X-145A. The microcrystalline wax preferably is present in the bar in an amount ranging from about 0.5% to about 5% by weight. The microcrystalline wax ingredient imparts pliability to the bar at room temperatures.

Auxiliary plastic binders may be incorporated into the bar at levels of from 0% to about 10%. These binders may be selected from monoglycerides, polyethylene glycols, fatty alcohols, sugars, tallow alcohol ethoxylates, and mixtures thereof. Other plastic binders are identified in the published literature, such as J. Amer. Oil Chem. Soc. 1982, 59, 442. The binder system can contain several plasticizers.

The syndet bar of this invention may comprise 0% to about 5% of a suitably fast hydrating cationic polymer. The polymers have molecular weights of from about 1000 to about 3,000,000.

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-

(ethyleneoxyethy1ene dimethylammonio)propy1]urea dichloride].

Specific examples of members of the cationic polysaccharide 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 Celanese 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, ethoxypolyalkylene 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 galacto annan 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- tropes, colorants, and fillers such as talc, clay, calcium car¬ bonate and dextrin can also be used. Cetearyl alcohol is a mixture of cetyl and stearyl alcohols. 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 odor degradation. Anti- bacterials 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 inven- tion, and are incorporated herein by reference:

The syndet bars of this invention have a pH of from 4 to 9 in a 1% aqueous solution. The preferred pH is from 5 to 8, more preferably about 6.5 to 7.5.

Matrix Ratio Table A matrix of ratios and key ingredients of the present inven¬ tion is provided in following table. The Matrix Ratio Table shows the broad, preferred and more preferred levels and ratios of the several key ingredients. E.g., the bars of the present invention can have long chain alkyl sulfate at a level of 10-40% by weight of the bar and lathering mild synthetic surfactant at a level of 15-40% by weight of the bar. Their broad and preferred ratio ranges are, respectively, 2.5:1-0.3:1 and 2:1-0.4:1. Their more preferred and exemplified ratios are found in Examples 6 and 7 and are, respectively, 0.6:1/0.5:1. Another example of a reading of the Matrix Ratio Table is the lathering mild synthetic surfactant and paraffin which, respectively, have broad and preferred ratios of 4:1-0.4:1 and 2.5:1-0.5:1. In Examples 6 and 7, their ratios are, respectively, 1.7:1 and 0.9:1.

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

MATRIX RATIO TABLE

Laboratory Assessment of Bar The following test procedures are used to evaluate the critical bar performance attributes of mildness and bar processa¬ bility. Smear Test Procedure

Equ pment:

1. #2-202C Fisher Brand Hexagonal Polystyrene weighing dishes (4" x 3").

2. #14-366A Fisher Brand Spatula. 3. Balance capable of weighing to two decimal points.

4. 120^*F Temperature Room.

5. Timer. Test Method

1. Label and weigh the number of weighing dishes needed (two weighing dishes per sample, one labeled M for mush dish, one labeled S for soak dish).

2. Weigh the original bar and record the weight. Place bar in preweighed dish labeled S.

3. Add 30 mis room temperature city water to the dish containing the bar prototype (pour water down side of weighing dish).

Add 30 mis room temperature city water to the dish containing the control bar. When placing the bars in the dish make sure the bars are not touching the sides of the dishes.

4. Allow bars to soak in weighing dishes at room temperature for 2 hours undisturbed.

5. After 2 hours of soaking, pick bar up carefully and allow to drain into the same dish for 15 seconds.

6. After 15 seconds, invert bar and place in preweighed dish labeled M. 7. Weigh soaked bar and record.

8. Scrape the wet surface or mush from the bar, with a spatula, into the same preweighed dish labeled M, weigh and record, this is the "wet" smear grade. Best results for scraping are seen when the spatula is held loose in hand being careful not to gouge the bar or to scrape too deeply. When the surface of the bar no longer appears to look wet or shiny, scraping is completed. To eliminate variability of scraping from person to person, results from each test will be reported relative to the control placed in that test. 9. Weigh and record the scraped bar.

10. Place the soak dish, the mush dish, and the scraped bar in the 120'F Temperature Room for water evaporation for 48 hours.

11. After 48 hours, weigh and record the dry weight of the soak dish, the mush dish and the scraped bar.

12. Calculate the surface area of the scraped portion of the bar by measuring (in inches) length times width.

13. Add the number of dry grams of mush (smear) to the number of dry grams of soak. This is the "dry" smear grade in grams.

All series of testing should include control, and all samples should be run in duplicates. A maximum of 7 products (6 plus a control) can be tested at one time, and an interval of 10 minutes between every 4 samples should be allotted for the addition of water as to not allow any products a lag time for soaking longer than 2 hours. Bar Soap Handwash Lather Volume Test

The handwash lather test is used to provide in-use lather volume measurements for the lather performance of skin cleansing bars. The test measures both the ultimate lather volume generated and the volume which is generated after a very short lathering period (to reflect lathering ease). The lather volumes are generated under soil-loaded conditions.

Synthetic soil is used for the soil-loaded lather volume test reported herein. Its formula and procedure for making it are set out below.

TABLE 1 Synthetic Soil

h Robeco Chemicals, Inc., New York, New York

Procedure

1. Heat above materials together stirring continuously between 160-175'F.

2. Mix 25 parts of above formula with 25 parts of a 5% to 80% tallow/20% coconut soap solution and 50 parts of distilled water at 150"F.

3. Cool mixture to room temperature while stirring constantly.

4. Store in covered glass container. Equipment The following equipment is used:

1. Water source and sink with temperature control. The water source should be medium hardness (6-9 grain/gallon) for most testing, although water of lower and higher hardness can be used for special purposes.

2. Synthetic soil (see Table 1).

3. Paper towels. 4. Test bars.

5. Control bars. Procedure

The following procedure is used: 1. Set temperature at 95-100'F. 2. Rub 0.22 cc of soil on hands.

3. Wet hands.

4. Rotate bar 3 times in both hands.

5. Add a little water, rub both hands 5 times.

6. Rotate hands 3 times (without soap), grade for flash volume. 7. Rotate 7 more times, grade for ultimate volume.

8. Collect lather and deposit on sink top.

9. Compare volume with standard bar target volume and assign grade.

Grading Scale Soil Loaded

7 - Exceptional

6 - Very much higher than target

5 - Higher than target

4 - Target volume 3 - Slightly lower than target

2 - Lower than target

In Vitro Skin Barrier Penetration Test (Mildness) This test was performed according to the procedure described in U.S. Pat. No. 4,812,253, Small et al . , issued Mar. 14, 1989, said patent incorporated herein by reference.

Frequently, materials which tend to improve processability also tend to have other negatives, particularly in terms of product mildness. Referring to Table 2, using the barrier destruction method to assess product mildness, individual raw materials sodium cetearyl sulfate is shown to be surprisingly more mild than the ultra mild sodium cocoglycerylether sulfonate, as well as a shorter chained AS, sodium dodecyl sulfate. The lower the number in Table 2 the milder the product.

TABLE 2

Mq 3H?Q Transported Water 0.137

Sodium Cetearyl Sulfate 0.302

Sodium Cocoglycerylether Sulfonate 0.458 Sodium Dodecyl Sulfate 1.289

Sodium Laurate 1.805

A Method of Making Syndet Bars Crutchinq

1. Add melted sodium cetearyl sulfate to the crutcher.

2. Add predetermined quantity of Hamposyl L-30 solution to the crutcher mix.

3. Add the predetermined quantity of AGS paste to the water in the crutcher. The AGS paste can be at ambient temperature or preheated to 150^βF (65"C).

4. Turn on the agitator and recirculation pump and maintain temperature in crutcher at 130-150'F (54-65'C) by adjusting steam and water valves.

5. Allow contents in crutcher mix to return to 130-150^βF (54-65'C) prior to adding predetermined quantity of stearic acid. 6. Add to heated crutcher mix predetermined quantity of soap or NaOH to form in-situ soap. 7. Allow the contents in the crutcher to mix and/or react for about 15 minutes while maintaining the temperature at 130-150'F (54-65'C). 8. Add sodium chloride plasticizer and titanium dioxide to the heated crutcher mix. 9. Add 1auric and/or coconut fatty acids to crutcher mix and allow contents of crutcher to mix for about 15 minutes while maintaining temperature at 130-150'F (54-65'C).

10. Add paraffin wax in a molten form and allow crutcher to mix approximately 1/2 hour until uniform. Dryi ng

The crutcher mix is dried and cooled using a combination flash chamber and chill roll or chill belt. The crutcher mix is first heated to approximately 300'F (149'C) by a heat exchanger and then flash dried in a chamber above the chill roll or chill belt. From the flash chamber the hot, dried mix is extruded onto the chill roll or chill belt. The chill belt or chill roll provides a uniform, thin, cool (85-95'F, 29-35'C) product in flake or chip form. Typical moisture for the flake is 1-10%, preferably about 2-4.5%. The ways to regulate the moisture, in the order of preference, are (1) increasing or decreasing steam pressure on the heat exchanger; (2) increasing or decreasing crutcher mix rate to the heat exchanger; and (3) increasing or decreasing crutcher mix temperature to the heat exchanger. Amalgamating

The flakes are weighed and mixed in a batch amalgamator to obtain uniform flake size. Preweighed perfume is added to the flakes and mixed in the amalgamator to obtain the desired finished product perfume level. The perfumed flakes are transferred to the mix hopper or directly to the plodder. Milling

The 3-roll soap mills are set up with the first roll at 120'F (49'C) and the other two mills at about 44'F (7'C). The material is passed through the mills several times to provide a homogeneous mixture of perfume and dried flakes. Plodding and Stamping

The plodder is set up with the barrel temperature at about 115'F (46'C) and the nose temperature at 114-122'F (45-50'C). The ideal plodder is a dual stage plodder that allows use of a vacuum of about 15-25 inches of Hg. The plugs should be cut in 5" sections and stamped with a cold die block using die liquor such as alcohol, if appropriate.

EXAMPLES AND FORMULAS The following formulas and examples are illustrative and are not intended to limit the scope of the invention(s) . The methods of making milled bars are well known. All levels and ranges, temperatures, results etc., used herein are approximations unless otherwise specified. The bars of this invention in the Formulas and Examples all have a pH of about 7 to about 7.5.

The level of the water in the above syndet bars stabilizes upon storage from about 3.75% to about 2%-3%.

COMPARATIVE EXPERIMENTAL FORMULA A Comparative Experimental Formula A is the control bar for assessing lather and/or smear of the bar of this invention. Comparative Formula A is typical of an alkyl sulfate-based product disclosed in commonly assigned, copending U.S. Pat. Application Ser. No. 07/605,614, supra. Formulas 1 through 7 described below have improved smears compared to Comparative Formula A, without sacrificing processability. In some cases of Formulas 1 through 7, the lather volume has been reduced, these are included to teach the scope of the patent. Acceptable soil lather grades are those that are of magnitude 3.0 or greater.

FORMULAS 1-3 Formula 1 demonstrates the large improvement in smear (lower numbers) upon incorporation of 21% paraffin wax relative to Comparative Formula A. See bottom of Table 3. Formulas 1-3 demonstrate the surprising benefit that paraffin waxes can impart to syndet bars containing long chain alkyl sulfates. Formula 2 further demonstrates that paraffin wax of a higher melting point (155'F/69'C) than that used in Formula 1 still provides an improved smear but without the large detriment to lather that the lower melting point (135^*F/59^*C) paraffin imparted to Formula 1. Formula 3 contains a mixture of the two paraffins which demon- strate intermediate properties between Formulas 1 and 2.

Formulas 4 through 6 demonstrate the effects of auxiliary plasticizers such as polyethylene glycol (PEG) on the paraffin- containing long chain alkyl sulfate matrix. Formula 4 has lower (better) smear (3.3/1.6 vs. 3.8/1.7) than Formula 2, the dif¬ ference being the presence of PEG in Formula 2. This smear improvement is achieved with no detriment to lather volume (3.0/3.0). Formulas 5 and 6 differ in a similar way: Formula 6 (no PEG) has better smear than Formula 5; surprisingly, Formula 6 actually has improved lather as well. FORMULA 7 Formula 7 demonstrates that lather can further be improved by increasing the level of high lathering synthetic surfactants (Form. 6 with 12% vs. Form. 7 with 13%), such as sodium lauroyl sarcosinate, surprisingly without substantially harming smear (Form. 6 with 3.5 lather vs. Form. 7 with 4.0 lather, and Form. 6 with smears of 2.3 and 1.3 vs. Form. 7 with smears of 3.2 and 1.6).

Both Formulas 6 and 7 are highly preferred syndet bars which have very good lathers and improved smears while still being highly processable.

EXAMPLE I Example I is a highly preferred personal cleansing bar of the present invention. It is the same as Formula 6, except that sodium cocoyl isethionate (SCI) is used in place of sodium coco¬ glycerylether sulfonate (AGS).

EXAMPLES II and III Example II is similar to Example I, but 5% less cocoyl isethionate is used and 5% sodium isethionate is used. Example III is also similar to Example I, but a mixture of lauric and coconut fatty acids is used, and less lauric acid is used.

Advantages Examples I-1II retain all of the advantages of Formula 6, but replacing the AGS with SCI results in a bar with substantially improved processability. Specifically, the product is a little softer during extrusion, flakes are more friable, and the product (bar) is slightly less sticky. The next of these differences is improved processability and an improved personal cleansing bar.

WHAT IS CLAIMED IS:

Claims

Zϊ -

1. A personal cleansing bar comprising: from about 10% to about 40% of essentially saturated long chain C15-C 2 alkyl sulfate; from about 10% to about 40% of paraffin wax having a melting point of from about 130'F/54'C to about 180'F/82'C; from about 15% to about 40% lathering mild synthetic surfactant; and wherein said lathering mild synthetic surfactant is selected from C 2-C14 isethionate, C12-C14 alkyl glyceryl ether sulfonate, sodium lauroyl sarcosinate, and mixtures thereof; from about 8% to about 25% free fatty acid; from about 2% to about 15% soap; and from about 1.5% to about 10% water; and wherein at least about 10% of said bar is said mild lathering C12-C14 alkyl isethionate.

2. A personal cleansing bar comprising: from about 15% to about 35% of saturated long chain (C16-C18) alkyl sulfate; from about 3% to about 12% of soap; from about 18% to about 35% of lathering mild surfactant; from about 13% to about 35% of paraffin wax having a melting point of from about 140'F/60'C to about 165'F/74'C; and from about 2% to about 8% water; lauric (C12) and stearic (Ci6-Cιβ) free fatty acids having a ratio of from about 2.5:1 to about 1:2, said free fatty acids being present at a level of from about 10% to about 20%; and wherein said bar has a pH of from about 4.0 to about 9.

3. A personal cleansing bar comprising: from about 10% to about 40% of essentially saturated long chain (C15-C22 alkyl) synthetic surfactant selected from the group consisting of: alkyl sulfate, acyl isethionate, alkyl sarcosinate, alkyl glyceryl ether sulfo¬ nate, and mixtures thereof; from about 10% to about 40% of paraf¬ fin wax having a melting point of from about 130'F/54'C to about 180'F/82'C; from about 15% to about 40% lathering mild synthetic surfactant; and wherein said lathering mild synthetic surfactant is selected from C12-C14 isethionate, C12-C14 alkyl glyceryl ether sulfonate, sodium lauroyl sarcosinate, and mixtures thereof; and wherein at least about 10% of said bar is said mild lathering C12-C14 alkyl isethionate; from about 8% to about 25% free fatty acid; from about 2% to about 15% soap; and from about 1.5% to about 10% water.

4. The bar of Claim 1, 2 or 3 wherein said wax has a melting point of from about 140'F/60'C to about 165'F/74'C; and preferably wherein said wax has a melting point of from about 142'F/61'C to about lδO'F/71'C.

5. The bar of Claim 1, 3 or 4 wherein said bar contains from about 10% to about 20% of said free fatty acid; and preferably wherein said fatty acids are mixtures of lauric (C12) acid and stearic (Ciδ-Cis) acid having a ratio of from about 3:1 to a about 1:3.

6. The bar of Claim 5 wherein the ratio of said lauric acid to said stearic acid is from about 2.5:1 to about 1:2.

7. The bar of Claim 1, 2, 3, 4 or 5 wherein said lathering mild synthetic surfactant is selected from C12-C14 alkyl glyceryl ether sulfonate and sodium lauroyl sarcosinate and mixtures thereof.

8. The bar of Claim 7 wherein said C12-C14 alkyl isethionate and said sodium lauroyl sarcosinate have a ratio of from about 1:1 to about 3:1; preferably wherein said C12-C14 alkyl isethionate and said sodium lauroyl sarcosinate ratio is about 1.5:1 to about 2.5:1.

9. The bar of Claim 1, 2, 3, 5, 6, 7 or 8 wherein said wax melting point is from about 142'F/61'C to about 160*F/7 C, said water level is from about 2% to about 4%, and said pH is from about 6.5 to about 7.5; and wherein said long chain synthetic surfactant is a mixture of C16-C18 alkyl sulfate and Ciβ-Cis acyl isethionate.

10. The bar of Claim 9 wherein said bar contains from about 10% to about 20% of said free fatty acid and said long chain synthetic surfactant is predominately C15-C18 acyl isethionate.