WO1992013060A2

WO1992013060A2 - Binder systems for bar soaps

Info

Publication number: WO1992013060A2
Application number: PCT/US1992/000192
Authority: WO
Inventors: James Robert Schwartz; Wayne Ellis Eccard; Theresa Anne Bakken; Lawrence Allen Gilbert
Original assignee: The Procter & Gamble Company
Priority date: 1991-01-28
Filing date: 1992-01-13
Publication date: 1992-08-06
Also published as: IE920240A1; WO1992013060A3; CN1063894A; AR244796A1; AU1350192A; MA22403A1; TW215456B; TR26616A; MX9200332A

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, combined with a selected plasticizer binder system comprising selected free fatty acid, monoglyceride and polyethylene glycol which confers good processability and good bar-use properties on these products.

Description

BINDER SYSTEMS FOR BAR SOAPS BASED

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

BACKGROUND OF THE INVENTION Synthetic surfactant-based personal cleansing bars have attracted much interest recently because they tend to be milder to the skin than soap-based products. This mildness, however, comes with negatives to both the manufacturer and the consumer. The 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 prop¬ erties of poor lather, messy smear, bar softness, and, conse¬ quently, high wear rates.

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 18% by weight long chain alkyl sulfate having essentially saturated C15-C22' preferably Ciβ-Cis, alkyl chains, preferably cetearyl sulfate, and a selected three-component plasticizer binder system. preferably comprising a mixture of monoglyceride, fatty acid, and polyethylene glycol for improved lather and improved bar messiness. DETAILED DESCRIPTION OF THE INVENTION A mild synthetic surfactant-based (syndet) bar with improved processability, good lather and/or reduced messiness is indeed an advance in this art. The present invention provides such an improved syndet bar comprising: (1) from about 18% to about 55%, preferably from about 20% to about 45%, of Ci5-C22_> preferably C16-C18, essentially saturated long chain alkyl sulfates (syn¬ thetic surfactant); (2) from about 14% to about 50%, preferably from about 15% to about 40% of a binder system of selected plasti- cizers as set forth hereinafter in detail; and (3) from about 2% to about 10%, preferably from about 2% to about 8%, more prefer¬ ably 2% to about 4%, water. The preferred syndet bar also con¬ tains from about 10% to about 45%, preferably from about 15% to about 40%, of a high lathering, mild surfactant; and from 0% to about 20%, preferably from about 5% to about 15%, sodium soap.

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 tradeoff in formulations.

Bars with improved processability comprising long chain alkyl sulfate and selected binders are described in commonly assigned, copending U.S. Pat. Application Ser. No. 07/605,614, J.R. Schwartz, W.E. Eccard, T.A. Bakken, and L.A. Gilbert, filed Oct. 30, 1990. The present binder system yields bars having even better product performance in the areas of lather and/or bar messiness than those specifically exemplified in that patent application.

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. 5 An important element of the present invention is a three- component plastic binder system which comprises three selected categories of plasticizers: (a) one that is water-insoluble at room temperature (25'C) on the order of Ci6-C]8 alkyl mono¬ glyceride; (b) one that is partially water-soluble at room tem- - ^•■ perature on the order of C15-C18 free fatty acid; and (c) one that is water-soluble at room temperature on the order of PEG 8000. "Plasticizers" as used herein are organic materials that soften the bar matrix and make it less brittle. The plasticizers them¬ selves are typically soft plastic materials at normal room te - ¹⁵ peratures of from about 15^βC to about 30"C, preferably 25^βC. For the sake of brevity, the terms "monoglycerides," "free fatty acid," and "PEG" as used herein will broadly represent the cate¬ gories of the three-component binder system of this invention, unless otherwise specified. 0 The preferred selected plasticizers (plastics) are a mixture of: (a) fatty acid monoglyceride, (b) fatty acid, and (c) poly¬ ethylene (or polypropylene) glycol. The syndet bar of this invention contains from about 14% to about 50%, preferably from about 15% to about 40%, of total plasticizers. The preferred 5 binder system preferably contains at least: 2% C15-C22 fatty acid monoglyceride (mono), 2% polyethylene glycols (PEG) (or poly¬ propylene glycol (PPG)), and 10% C10-C20 free fatty acid (FFA), preferably C12-C18 FFA.

The molecular weights of the PEG and PPG and PEG/PPG can 0 range from about 1,000 up to about 200,000. A mixture of FFA is preferred. The FFA contains a ratio of C16-C20 FFA to C10-C1 FFA of from about 4:1 to about 1:1. A mixture of stearic and 1auric having a ratio of about 4:1 to 1:1 is more preferred, and a ratio of about 2.5:1 to 1:1 is even more preferred.

Some or all of the three plasticizers can be substituted with equivalent plasticizers, e.g., paraffin, fatty alcohol, sugar, tallow alcohol ethoxylates (TAE), e.g., TAEso_* TAEs, etc., and mixtures thereof. Other plasticizers (binders) are identified ^■*" the published literature, such as J. Amer. Oil Chem. Soc. 1982. 59, 442. The binder system can contain several plasticizers.

In Table 1 some percentages and ranges of the three key preferred plasticizers (plastics) used in the syndet bars of tne present invention are set out. The preferred ranges are from about 4% to about 8% monoglyceride; from about 3% to about 7% PEG

(or PPG); and from about 15% to about 22% free fatty acid. Low and high range levels for the selected plasticizers are also set out in Table 1. The level of monoglyceride can range from about 2% to about 15%, preferably from about 3% to about 10%, by weight of the bar. The level of PEG can range from about 2% to about

15%, preferably from about 3% to about 10%, and the level of free fatty acid can range from about 10% to about 30%, preferably fror about 14% to about 25%, by weight of the bar. The monoglyceride. PEG and FFA in Table 1 can be replaced in whole or in part wif¹ selected paraffin, sucrose, and fatty alcohol, respectively.

TABLE 1 Monoglyceride PEG Free Fatty Acid 2 - 15% 2 - 15% 4 - 30% 3 - ιo% 3 - 10% 14 - 25%

4 - 8% 3 - 7% 15 - 22% In the bars of the present invention the level of free fatty acid is preferably about equal to or greater than the sum of tne levels of the monoglyceride and the PEG (or PPG). The preferred ratio of monoglyceride to PEG is about 2:1 to about 1:1, as set out in Table 2.

TABLE 2 Ratio Ranges for Monoglyceride to PEG (or PPG) Preferred 2:1 to 1:1 4:1 to 1:4

3:1 to 1:3 The preferred high and low molecular weights (M.W.: c^{f D}E3 and PPG are, respectively, about 1,000-20,000 (preferably -i.GCO t: about 10,000) and 2,000-15,000. and are set out in Table 3. TABLE 3

PEG PPG M.W. High 20.000 15,000 Low I.000 2,000 The preferred monoglyceride compositions contain lower levels of impurities, di- and triglycerides, and shorter chained glycer- ides. See Tables 4 and 5. The more preferred monoglyceride is

95% or more mono- with 5% or less di- and triglycerides, and with 20% or less C14 or shorter alkyl chains.

TABLE 4 Monoglvcerides Di- and Triglycerides

80% 20% maximum

Preferred 90% 10% maximum More Preferred 95% 5% maximum

TABLE 5 Monoglyceride Alkyl Chains -16-18 ^cli or Shorter 70% 30% or less

80% 20% or less

In Table 6, eight (A-H) examples of binder systems for bar compositions are set out to show several levels of the key plasti- cizers of the present invention. Experimental Binder System Examples C and E do not contain all three of the key plasticizers. Binder System Example D makes a superior syndet bar. It contains all three key plasticizer ingredients. See Examples 3 and 4 in Tables 10 and 11. The "Other" column in Table 6 is the balance of the non-plastic bar ingredients such as surfactant, soap, etc.

TABLE 6

In Table 7, for example, a bar of the present invention containing 14% of a ono/PEG/FFA 2/2/10% binder system can contain other selected plasticizers, e.g., fatty alcohols, waxes, etc. In other words, the bars of the present invention can contain several plasticizers. The key is to balance the three-component system.

TABLE 7

Another essential element of the present invention is the surfactant system. The long chain alkyl sulfate (hereinafter including its long chain equivalent synthetic surfactants) is key and is defined herein, as comprising long chain 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 equivalent) is derived from corresponding saturated straight chain alcohols. The preferred alkyl sulfate has a ratio of C 6-C18 alkyl chains in the range of from about 100% Ci6 to about 100% Cχ8 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% Ciβ- 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 e ulsifier. 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 acyl isethionates and no more than 25% or lower C14 acyl groups are also useful. Preferred is stearoyl isethioniate with C1 3%; Cχ6 50%; and Ciβ 47%. 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 C16-C20. and mixtures thereof.

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. 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 ( H-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 alkylglycerylether sulfo- nate (AGS) surfactant based synbar comprising a "standard" alkyl- glycerylether sulfonate mixture. Barrier destruction testing surprisingly shows that the long chain alkyl sulfates are milder than standard AGS. The long chain alkyl sulfate comprises 18-55% by weight of the bars of this invention. Other syndet bar ingred¬ ients are selected from: other surfactants, polymeric skin feel aids, moisturizers, plasticizers, fillers, etc. A preferred syndet bar comprises: about 20-45% of cetearyl sulfate; 5-15% soap; and about 1-35%, preferably about 5-30%, moisturizer; 10-50% plasticizers; and 2-10%, preferably 3-8%, water. To insure mildness and bar firmness, the synthetic detergent surfactant system in the bars should contain the long chain alkyl sulfate and the total balance of the surfactant system at a ratio of about 2:1 to 1:2, more preferably about 1:1. Other detergent surfactants can be used; particularly from about 10% to about 50%, preferably from about 15% to about 40%, of a high lathering or lather enhancing surfactant, especially mild ones, e.g., sodium lauroyl sarcosinate, alkylglycerylether sul- fonate, and sulfonated fatty acids. A "high lathering surfactant" is one which lathers better than the long chain alkyl sulfate.

Numerous examples of such 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 glutamates, acyl isethionates, alkyl sulfosuc- cinates, 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 sulfates. Alkyl chains for these other surfactants are Cs-C 2_> preferably Cio-Cis- Alkyl glyco- sides 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 shorter chain or traditional (coconut) alkyl sulfates and still maintain the mildness requirement of the bar.

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.

A preferred synbar contains a mixture of polyethylene glycol and monoglyceride at a ratio of from 1:4 to 4:1. The preferred polyethylene glycol has a molecular weight greater than 1,000. The preferred monoglyceride has a di- and triglyceride content below 20% of the total monoglyceride and an alkyl chain length distribution of at least about 50% C15 or longer alkyl chain.

A preferred AS syndet bar also contains from about 10% to about 35% moisturizer, preferably one selected, from glycerin and free fatty acid or mixtures thereof. In this case, the free fatty acid serves the purpose as moisturizing and plasticizer ingredient.

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- (ethyleneoxyethylene dimethylammonio)propyl]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-dι- allyl ,N-N-dialkyl ammonium chloride available from National Starcn

Corporation under the trade name Celquat.

The cationic synthetic polymers useful in the present ir- vention are cationic polyalkylene imines, ethoxypolyal ylene imines, and pol [N-[-3-(dimethylammonio)propyl]-N'-[3-(ethylene¬ oxyethylene dimethylammonio)propyl]urea dichloride] the latter of which is available from Miranol Chemical Company, Inc.. under t^e trademark of Miranol A-15, CAS Reg. No. 68555-35-2.

Preferred cationic polymeric skin conditioning agents of tne present invention are those cationic polysaccharides of t e cationic guar gum class with molecular weights of 1,000 to 3,000,000. More preferred molecular weights are from 2.500 t; 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- 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:

Inventor(s) Morshauser Oberstar et al . Bolich et al . Hoski..s et al .

Grollier Small et al . Saud

Small et al . Medcalf et al.

Rys et al . The syndet bars of this invention have a pH of from 4 to 9 in a 1% aqueous solution. The preferred pH is 5 to 8, more prefer¬ ably about 7.

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

Bar Character Smear Tests 5 ml and Soap Dish Smear Test Eouip ent

"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°C/80'F/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. Graαe Smear Description 10 Superior 9 Excellent 8 Very good smear 7 Good smear (Target)

6 Slightly poorer than desired 5 Marginal but still acceptable 4 Minimum acceptable smear 3 Poor and unacceptable 2 Very poor smear

1 Poorest normally seen

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 8 Synthetic Soil

100.00% ^a Emery Industries, Inc., Cincinnati, Ohio ^D Emery Industries, Inc., Cincinnati, Ohio ^c Armour Industrial Chemical Co., Chicago, Illinois - Armour Industrial Chemical Co., Chicago, Illinois - Armour Industrial Chemical Co., Chicago, Illinois f Armour Industrial Chemical Co., Chicago, Illinois 9 Hu ko Products, Memphis, Tennessee h Robeco Chemicals, Inc., New York, New York

Procedure 1. Heat above materials together stirring continuously between 160-175^βF.

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. Eouipment

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 8).

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 9, 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 9 the milder the product.

TABLE 9 g H;>0 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 Crutching

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^βC) 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 to heated crutcher mix the predetermined quantity of acyl isethionate. Allow contents in crutcher to mix for about 20 minutes while maintaining temperature at 130-150'F (54-65'C). 9. Add sodium chloride plasticizer and titanium dioxide to the heated crutcher mix.

10. 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). Drying

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 (Optional)

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 125'F (52'C) and the nose temperature at 120'F (49'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 The following 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 all have a pH of about 7 to about 7.5.

COMPARATIVE EXPERIMENTAL EXAMPLES 1 AND 2 Comparative Experimental Examples 1 and 2 are the control bars for assessing lather and/or smear of the bar of this inven¬ tion. Comparative Example 1 is typical of an alkyl sulfate-based product disclosed in commonly assigned, copending U.S. Pat. Application Ser. No. 07/605,614, supra. Examples 3 and 4 de¬ scribed below have improved smears compared to Comparative Example 1, without sacrificing processability and lather properties as Comparative Example 2. Note that Comparative Examples 1 and 2 lack one of the essential plasticizers of the binder system of the present invention. EXAMPLE 3 Example 3 demonstrates the surprising benefits of incor¬ porating a small amount of a non-surfactant, water-soluble plasti¬ cizer (e.g., PEG-8000) with a comparatively water-insoluble plasticizer (such as monoglyceride) and a partially water-soluble plasticizer, free fatty acid. Comparative Experimental Example 2, with 10% glyceryl monostearate plus 19% free fatty acid, has improved smear but poor lather when compared to Comparative Experimental Example 1. Example 3, which has 6% glyceryl mono- stearate and 4% PEG-8000 (a ratio of about 1.5:1), has unex¬ pectedly good lather and good smear. The low level of PEG-8000 provides in Example 3 improved lather over Example 2 containing glyceryl monostearate without deleteriously impacting lather properties. TABLE 10

Comparative Comparative x Ex. 2 Ex. 3

Comparative Experimental Example 1 is good for lather, but marginal in smear. Comparative Experimental Example 2 is good in smear, but marginal in lather. Note that Example 3 has lathers of 4.0 and 4.75 vs. 2.0 and 2.0 of Comparative Experimental Example 2. Comparative Experimental Example 2 has improved smear with respect to Comparative Example 1. Surprisingly, Example 3 has both improved lather and improved bar smears.

TABLE 11

Example 4 is a highly preferred bar of the present invention with slightly reduced lathers compared to Example 3, but with improved smears (not shown). Comparative Experimental Examples 5 and 6 show that a free fatty acid component containing more lauric acid than stearic acid adversely affects lather. Examples 3 and 4 have unexpectedly superior lather over Experimental Examples 5 and 6. Examples 3 and 4 are highly preferred syndet bars which have improved lather and improved smear while still being highly processable. The level of the water in the above syndet bars stabilizes upon storage at about 2%-3%.

WHAT IS CLAIMED IS:

Claims

CLAIM5

1. A personal cleansing syndet bar comprising: frcm 18% to 55% of essentially saturated long chain C-₅-C _ alkyl sulfate; frcm 14% to 50% of a plastizer binder system comprising, by weight of the bar: (a) frcm 2% to 15% monoglyceride; (b) frcm 2% to 15% polyethylene glycol having a m of from 1,000 to 200,000; and (c) from 10% to 30% C_1Q-C₂₀ free fatty acid; and wherein said free fatty acid contains C-₆-C₂₀ free fatty acid and C_1Q- free fatty acid having a ratio of 4:1 to 1:1; and from 2% to 10% water; and vfoerein said syndet bar has a pH of frcm 4.0 to 9.

2. The personal cleansing syndet bar of Claim 1 wherein said bar contains from 20% to 45% of said saturated long chain alkyl sulfate; frcm 0% to 20% of soap; from 10% to 40% of a high lathering, mild surfactant; from 15% to 40% of said plastizer binder system; and from 2% to 8% water; and wherein said free fatty acid is stearic (C₁₆~C₁₈) acid and lauric (C_₂) acid having a ratio of 4:1 to 1:1; wherein said monoglyceride is composed of alkyl chain lengths of G,- and C.- and has diglyceride and triglyceride total content of less than 20% by weight of the glycerides; wherein said polyethylene glycol has an average molecular weight of from 2,000 to 20,000.

3. The syndet bar of Claim 1 or 2 wherein said polyethylene glycol molecular weight is frcm 4,000 to 10,000; wherein the ratio of said polyethylene glycol to said monoglyceride is from 1:4 to 4:1.

4. The syndet bar of Claim 1, 2 or 3 wherein said ratio of said polyethylene glycol to said monoglyceride is from 1:2 to 1:1; and wherein said bar contains from 5% to 15% sodium soap and from 15% to 40% of a high lathering, mild surfactant selected frcm anionic acyl sarcosinates, alkyl sulfosuccinates, alkylglycerylether sulfαnates, betaines, sulfonated fatty acids, and mixtures thereof; and frcm 2% to 4% water; and wherein the level of said polyethylene glycol is frcm 3% to 10%; and wherein the level of said monoglyceride is from 4% to 15%; and wherein said level of free fatty acid is from 14% to 25% and said stearic acid and said lauric ratio is from 2.5:1 to 1:1.

5. The syndet bar of Claim 1, 2, 3, or 4 wherein said plasticizer binder system contains, by wei t of said plastic binder system, frcm 2% to 50% of a secondary plasticizer selected from water-soluble sugars and polysaccharides, water-soluble organic salts, paraffins, fatty esters, fatty ethers, and mixtures thereof; and wherein said secondary plasticizer is present at a level equal to or less than the level of the total of said monoglyceride, free fatty acid, and polyethylene glycol; and wherein said monoglyceride and said polyethylene glycol have a ratio of from 2:1 to 1:1.

6. The syndet bar of Claim 1, 2, 3, 4 or 5 wherein said soap- synthetic bar contains other ccπpαnents selected frcm: moisturizers, colorants, solvents, fillers, other surfactants, polymeric skin feel and mildness aids, perfumes, and preservatives, and water at a level of from 3% to 8%.

7. A personal cleansing syndet bar comprising: from 18% to 55% of essentially saturated long chain C₁₅- acyl isethionate; and from 10% to 40% of a hiφi lathering, mild surfactant; from 14% to 50% of a plastic binder system comprising: frcm 2% to 15% monoglyceride and from 2% to 15% polyethylene glycol and frcm 10% to 30% C_1Q- ₂₀ free fatty acid wherein said free fatty acid contains stearic (C₁₆- _lg) acid and lauric (C ) acid at a ratio of 4:1 to 1:1; frcm 0% to 20% of soap and from 2% to 10% water; and wherein said syndet bar has a pH of from 4.0 to 8.5.

8. A personal cleansing syndet bar comprising: frcm 18% to 55% of essentially saturated long chain C. - ₂_ alkyl sulfate; frcm 14% to

50% of a plasticizer binder system comprising, by weight of the bar:

(a) frcm 2% to 15% monoglyceride; (b) from 2% to 15% polyethylene glycol; and (c) from 10% to 30% C _-C free fatty acid, said free fatty acid having a C,,,-C,₀ acid and C,_n-C, . acid ratio of from 4:1 to

16 18 10 14

1:1; frcm 0% to 20% of soap; from 10% to 40% of a high lathering, mild surfactant; and frcm 2% to 10% water; and wherein said syndet bar has a pH of frcm 4.0 to 9.

9. The personal cleansing syndet bar of Claim 8 wherein said bar contains frcm 20% to 45% of said saturated long chain alkyl sulfate; from 15% to 40% of said plasticizer binder system; and from 2% to 4% water; and wherein stearic (C₁₆- ₁₈) acid and lauric acid are present at a ratio of 4:1 to 1:1; and wherein said monoglyceride and polyethylene have a ratio of from 3:1 to 1:3; preferably wherein said monoglyceride is coπposed of alkyl chain lengths of C._g and C_χ8 and wherein said polyethylene glycol has an average molecular weight of frcm 2,000 to 20,000; and wherein the ratio of said polyethylene glycol to said monoglyceride of said plasticizer binder system is from 1:2 to 1:1; more preferably wherein said fatty acid is a mixture of stearic acid and lauric acid having a ratio of frcm 2.5:1 to 1:1; wherein said bar contains frcm 5% to 15% sodium soap and from 15% to 40% of a high lathering, mild surfactant selected from anionic acyl sarcosinates, alkyl sulfosuccinates, alkylglycerylether sulfonates, betaines, sulfonated fatty acids, and mixtures thereof; and from 2% to 4% water; and wherein the level of said polyethylene glycol is from 3% to 10%; and

the level of said monoglyceride is frcm 4% to 15%; and wherein said level of free fatty acid is from 14% to 25% and said free fatty acid contains stearic acid and lauric acid at a ratio of from 2.5:1 to 1:1.

10. The syndet bar of Claim 9 wherein said plasticizer binder system contains, by weight of said plastic binder system, from 2% to 50% of another plasticizer selected from water-soluble sugars and polysaccharides, water-soluble organic salts such as sodium isethionate, paraffins, fatty esters, fatty ethers, and mixtures thereof; and vderein said another plasticizer is present at a level equal to or less than the level of the total of said monoglyceride, free fatty acid, and polyethylene glycol; preferably wherein said soap-synthetic bar contains other components selected from: moist¬ urizers, colorants, solvents, fillers, polymeric skin feel and mildness aids, perfumes, and preservatives, and water at a level of frcm 3% to 8%.