WO1996004360A1

WO1996004360A1 - Transparent personal cleansing bar

Info

Publication number: WO1996004360A1
Application number: PCT/US1995/009436
Authority: WO
Inventors: Benjamin Carl Wiegand; Alejandro Figueroa; Michael August Brunsman; Alexandre Zyngier
Original assignee: The Procter & Gamble Company
Priority date: 1994-08-03
Filing date: 1995-07-26
Publication date: 1996-02-15
Also published as: EP0775194A1; CZ31797A3; HUT76683A; CN1157632A; JPH10503546A; CA2196536A1; CA2196536C; PE29096A1; BR9508500A; KR100235692B1; AU3148995A; TW341598B; MX9700843A

Abstract

This invention relates to transparent pour molded personal cleansing bars which exhibit desirable hardness characteristics. These transparent bars are mild, low smearing and exhibit good lathering characteristics. The transparent bars of the present invention comprise: from 18 parts to 35 parts soap, wherein said soap comprises at least 50 % insoluble sodium soap; from 14 parts to 32 parts water; from 5 parts to 37 parts lathering synthetic surfactant; wherein said lathering synthetic surfactant has a critical micelle concentration equilibrium surface tension between 10 and 50 dynes/cm, as measured at 25 °C; and from 18 parts to 37 parts of a water soluble organic solvent.

Description

TRANSPARENT PERSONAL CLEANSING BAR

TECHNICAL FIELD

This invention relates to transparent and translucent pour molded personal cleansing bars. These bars are mild, low smearing and exhibit good lathering characteristics. These bars also have desirable hardness characteristics.

BACKGROUND OF THE INVENTION

Transparent personal cleansing bars are well known in the art and are considered desirable by many consumers. Unfortunately, a problem in formulating transparent personal cleansing bars is that, either they can be too harsh, as in the case of bars containing high levels of soap, or they can be undesirably soft. For example, U.S. Patent 5,041 ,234 to Instone, et. al, issued Aug. 20, 1991 , discloses a transparent bar which contains greater than 40 parts of soap (high soap bar).

Like other "high soap" transparent bars, the bars disclosed by Instone et al have good lather, low smear, and good bar hardness. Such high soap level transparent bars, however, are rather harsh to the skin. Another drawback to such bars is that their processing generally require the use of an undesirable solvent, such as volatile short chain monohydric alcohols, or require special milling to obtain transparency.

Transparent bars which contain lower levels of soap are also known in the art. "Lower soap" transparent bars contain less than 40 parts of soap. U.S. Patent 5,002,685 to Chambers and Instone, issued Mar. 26, 1991 , discloses a transparent bar made with 25 to 34 % soap, 5 to 15 % monohydric alcohol, 15 to 30 % sugar and/or cyclic polyol, and 15 to 30 % water. The Chambers et al. soap mixture, however, consists of 18 % to 26 % soluble soaps and 8 to 16 % insoluble soap. The Chambers et al. transparent bar is, thus made with mostly soluble soap. Unfortunately, personal cleansing bars which contain less than 50% insoluble soap (e.g., greater than 50% soluble soap) can be unacceptably soft.

Chambers, however, actually teaches away from the use of high levels of insoluble soaps. In particular, Chambers et al. reports that bars, Examples 37 and 38, which contain "between 30 and 20 wt % insoluble soaps and 10 wt % or less of soluble soaps had inferior user properties due to their low level of soluble soaps. " (Col. 8, II. 1 -3) The processing of this Chambers et al. bar also require the use of undesirable volatile monohydric alcohol solvent. U.S. Patent 4, 165,293 to Gordon, issued Aug. 21 , 1 979, also discloses personal cleansing bars wherein the soap component comprises less than 50% insoluble soap. In particular, Gordon discloses a monohydric alcohol free process for making a transparent soap bar made with "mainly ... tallow soap". It is noted here that "tallow soap" typically consists of approximately 51 %, by weight, of soluble soap and can thus be characterized as mainly soluble soap. Moreover, the transparent soap bars disclosed by Gordon preferably comprise a blend of 80-90% tallow soap and 10-20% coconut soap. The soap component within such a transparent bar would contain from 55% to 59% soluble soap.

U.S. Patent 5,264,144 to Moroney et al., issued Nov. 23, 1993 and U.S. Patent 5,340,492 to Kacher et al., issued Aug. 23, 1 994, disclose personal cleansing bars comprising a fatty acid soap (including both soluble and insoluble soaps), water and synthetic surfactants (i.e., anionic, amphoteric and nonionic). However, the personal cleansing bars taught by Moroney et al are not transparent, and the personal cleansing bars taught by Kacher et al are not necessarily transparent. Moreover, there is no teaching in either reference about the preparation of a transparent cleansing bar. It has now been discovered that personal cleansing bars which contain from 18 to 35 parts of soap, wherein the soap comprises at least 50% insoluble soap are transparent and exhibit desirable hardness characteristics. These personal cleansing bars are also mild to the skin, low smearing and exhibit good lathering characteristics. Moreover, the preparation of these transparent bars does not require the use of monohydric alcohols.

SUMMARY OF THE INVENTION This invention relates to transparent pour molded personal cleansing bars which exhibit desirable hardness characteristics. These transparent bars are mild, low smearing and exhibit good lathering characteristics. The transparent bars of the present invention comprise: from 1 8 parts to 35 parts soap, wherein said soap comprises at least 50 % insoluble sodium soap; from 14 parts to 32 parts water; from 5 parts to 37 parts lathering synthetic surfactant; wherein said lathering synthetic surfactant has a critical micelle concentration equilibrium surface tension between 10 and 50 dynes/cm, as measured at 25°C; and from 18 parts to 37 parts of a water soluble organic solvent, wherein the combined level of water and water-soluble organic solvent is at least 40 parts.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to transparent pour molded personal cleansing bars which exhibit desirable hardness characteristics. These transparent bars are mild, low smearing and exhibit good lathering characteristics.

The transparent bars of the present invention comprise: (A) from 18 parts to 35 parts soap, wherein said soap comprises at least 50 % insoluble sodium soap; (B) from 5 parts to 37 parts lathering synthetic surfactant; wherein said lathering synthetic surfactant has a critical micelle concentration equilibrium surface tension between 10 and 50 dynes/cm, as measured at 25°C; (C) from 14 parts to 32 parts water; and (D) from 1 8 parts to 37 parts of a water soluble organic solvent. For purposes of the present invention a bar is considered to be transparent if 14 point type can be read through a 1 /4 inch thickness of the bar. A bar is not transparent if 14 point type cannot be read through a 1 /4 inch thickness of the bar. See, Gordon; U.S. Patent 4, 1 65,293; Issued August 21 , 1979, herein incorporated by reference. As used herein, the term "insoluble soap" means a fatty acid sodium soap that is less soluble than sodium myristate.

The transparent bars of the present invention are preferably prepared without the use of monohydric alcohols. As a result, the transparent bars of this invention are very stable weight wise. Alcohol free bars are also more economical to - prepare. Some volatile monohydric alcohols (e.g., ethanol, propanol, butanol) can be used. However, the preferred bars of this . invention are essentially free of monohydric alcohols. Care must be used when using monohydric alcohol solvents due to their potential explosive nature. The levels, parts, percentages and ratios herein are by weight unless otherwise specified. Note that the "soap mixtures" are expressed herein as weight percent (wt. %) of the soap." On the other hand, "parts" are used herein as weight parts of the finished bar. All numerical limits, ranges, ratios, etc., are approximations unless otherwise specified.

The individual components of the transparent personal cleansing bars of the present invention and the particular ways in which these components are desirably combined are disclosed in detail as follows.

SOAP: The transparent bars comprise from about 18 parts to about 35 parts, preferably from about 20 parts to about 32 parts, more preferably from about 24 parts to about 32 parts soap. Surprisingly, at soap levels above about 35 parts a transparent bar is not produced, and at soap levels below about 18 parts the bar is unacceptably soft.

The soap mixture of this invention comprises at least 50% insoluble sodium soap, preferably from 50 % to about 87 % insoluble sodium soap, more preferably from about 53% to about 72% insoluble sodium soap. Transparent bars wherein the soap component contains less than 50% insoluble soap can be undesirably soft.

As hereinbefore described, the term "insoluble soap" is defined herein as: A fatty acid sodium soap that is less soluble than sodium myristate. In particular, the term "insoluble soap" refers to monovalent salts of saturated fatty monocarboxylic acids having a carbon chain length of from 16 to 24, preferably from 18 to 24. These monovalent salts would normally be sodium salts, although some cations, such as K, Mg or alkanolammonium ions could be used. The preferred insoluble fatty acid soap is selected from the group consisting of sodium palmitate and sodium stearate and mixtures thereof. Other insoluble soaps, particularly, higher fatty acid insoluble soaps, can also be used.

The remainder of the soap mixture is soluble soap. The term "soluble" soap refers to the monovalent salts of saturated fatty monocarboxylic acids having a carbon chain length of from 8 to 14 and additionally the monovalent salts of oleic acid and polyunsaturated fatty monocarboxylic acids having a carbon chain length of between 8 and 22. We define sodium myristate as a "soluble" soap. The preferred soluble soaps are selected from the group consisting of: myristic, oleic and lauric acid soaps and mixtures thereof.

The fatty acid soap used in the transparent bars of the present invention can be made using either pure chain fatty acids, mono-, di-, or triglycerides or oils, or by using the proper levels and ratios of common fatty acid and oil mixtures such as coconut, palm oil stearin, tallow, and triple pressed stearic. The term "coconut" is defined herein in connection with soap or fatty acid mixtures to refer to materials having an approximate carbon chain length distribution of: 8 % Cβ; 7 % C-\ Q; 48 % C12; 17.5 % C-J4; 9 % C*| β; 2 % C*] g; 6 % oleic and 2.5% linoleic. Coconut soap thus comprises approximately 1 1 % insoluble soap and 89 % soluble soap.

The term "babassu" is defined herein in connection with soap or fatty acid mixtures to refer to materials having an approximate carbon chain length distribution of: 6 % CQ; 3 % C1 -3; 46 % C12; 20 % C1 ;

7 % C-J 6 and 18 % C-| 8.1 oleic. Babassu soap thus comprises approximately 7 % insoluble soap and 93 % soluble soap.

The term "triple pressed stearic" as defined herein refers to fatty acids having an approximate chain length distribution of 5 % myristic

(C14), 50 % palmitic (C16) and 45 % stearic (C18). Triple pressed stearic soap thus comprises approximately 95 % insoluble soap and 5 % soluble soap.

The term "hardened tallow" is defined herein to refer to fatty materials having an approximate chain length distribution of 3 % myristic (C14), 50 % palmitic (C16) and 45 % stearic (C18), and 2% oleic. Hardened tallow soap thus comprises approximately 95 % insoluble soaps and 5 % soluble soaps.

By comparison, "tallow" is defined (normalized mid range values from Table 6.34 Bailey's Industrial Oil and Fat Products, Volume 1 , Wiley Intersciences) as a mixture of soaps having an approximate chain length distribution of: 4 % C14; 29 % C16; 20 % C18; 2 % palmitoleic; 42 % oleic and 3 % linoleic. Tallow soap thus comprises approximately 49 % insoluble soap and 51 % soluble soap.

The amount of free fatty acid incorporated into the finished bars of the invention typically ranges from 0.5 parts to 3 parts, more typically from 1 to 2 parts. However, no free fatty acid is required. The free fatty acid component is preferably introduced into the soap mixtures of the present invention by addition of fatty acid to the soap mixtures after the saponification of the soap mixture has taken place. The free fatty acid component can also be introduced as a prepared mixture of soap and free fatty acid, such as an acid-reacting mixture of soap and free fatty acid prepared by under-neutralization in the soap making process. The fatty acid soap of the present invention comprises sodium soaps. However, low levels of non-sodium soaps such as potassium, magnesium, and/or triethanolammonium (TEA) soaps are permissible. Such non-sodium soaps, when used, are preferably used at a level of from 0 to 10 parts, preferably from 0 to 5 parts by weight of the bar soap.

WATER: The water level in the bar ranges from about 14 parts to about 32 parts, preferably from about 18 parts to about 27 parts, more preferably from about 22 parts to about 26 parts. The higher levels of water within these preferred ranges are more preferred for processing ease, bar mildness and other advantages.

The water level within the personal cleansing bars herein is critical to obtain a transparent bar having desirable hardness characteristics. When the water is less than about 14 parts by weight of the bar, the bar may not be transparent. When the level of water present in the bar exceeds about 32 parts by weight of the bar, the bar can be unacceptably soft.

SURFACTANT: The lathering synthetic surfactant level in the bar ranges from about 5 parts to about 37 parts, preferably from about 10 parts to about 28 parts, more preferably from about 12 parts to about 22 parts by weight of the finished bar. The synthetic surfactant is necessary for improving bar characteristics. Some of these characteristics include lathering/sudsing properties, bar mildness, rinse feel of the bar, and smear/hardness characteristics.

The bar composition comprises a lathering synthetic surfactant selected from the group consisting of anionic surfactants; nonionic surfactants, zwitterionic surfactants, amphoteric surfactants, and mixtures thereof. The lathering surfactant is defined herein as a synthetic surfactant or a mixtures of surfactants that has an equilibrium surface tension of between 10 and 50 dynes/cm, more preferably between 20 and 45 dynes/cm as measured at the CMC (critical micelle concentration), at 25°C. Some surfactant mixtures have surface tensions lower than some of its components. Thereby both low and high lathering and high and low water-soluble surfactants can be used in the bar compositions of the present invention. Suds boosting synthetic detergent surfactants and/or synthetic detergent surfactants that are known as good dispersants for soap curds that are formed in hard water, are particularly desirable.

A preferable selection of lathering synthetic surfactant would include a mixture of anionic and zwitterionic/amphoteric surfactants. The addition of the zwitterionic/amphoteric surfactant allows for increased mildness and lather properties. However, this addition also can lead to worse structure forming properties in the bar, so that the amount of amphoteric surfactant should be kept to less than 10 parts. Preferred zwitterionic/amphoteric surfactants are selected from alkyl ampho mono and di-acetates, alkyl betaines, alkyl sultaines, alkyl amidopropyl betaines, alkyl amidopropyl hydroxysultaines, and mixtures thereof, wherein said surfactants contain C8 to C22 alkyl chains and mixtures thereof.

Examples of suitable synthetic surfactants for use herein are those described in U.S. Pat. No. 3,351 ,558, Zimmerer, issued Nov. 7, 1967, at column 6, line 70 to column 7, line 74, incorporated herein by reference; and U.S. Patent 4,165,293 to Gordon, issued Aug. 21 , 1979; U.S. Patent 5,002,685 to Chambers and Instone, issued Mar. 26, 1991 ; U.S. Patent 5,041 ,234 to Instone, et al., issued Aug. 20, 1991 ; all incorporated herein by reference in their entirety. They include alkyl sulfates, anionic acyl sarcosinates, methyl acyl taurates, N- acyl glutamates, acyl isethionates, alkyl sulfosuccinates, alkyl phosphate esters, ethoxylated alkyl phosphate esters, trideceth sulfates, protein condensates, mixtures of ethoxylated alkyl sulfates and alkyl amine oxides, betaines, sultaines, and mixtures thereof. Some preferred surfactants are the alkyl ether sulfates with 1 to 12 ethoxy groups, especially ammonium and sodium lauryl ether sulfates.

Synthetic sulfate detergents of special interest are the normally solid alkali metal salts of sulfuric acid esters of normal primary aliphatic alcohols having from 10 to 22 carbon atoms. Thus, the sodium and potassium salts of alkyl sulfuric acids obtained from the mixed higher alcohols derived by the reduction of tallow or by the reduction of coconut oil, palm oil, palm kernel oil, palm oil stearin, babassu kernel oil or other oils of the coconut group can be used herein. Other aliphatic sulfuric acid esters can be suitably employed. Certain hygroscopic synthetic surfactants which are normally used in liquids and which are very difficult to incorporate into normal cleansing bars are very compatible in the bars of the present invention. Thus, essentially all of the known synthetic surfactants which are useful in cleansing products are useful in the compositions of the present invention. The cleansing product patent literature is full of synthetic surfactant disclosures. Preferred synthetic surfactant systems are selectively designed for bar appearance, stability, lather, cleansing and mildness.

The preferred lathering synthetic surfactant is selected from the group consisting of: acyl isethionates, acyl sarcosinates, alkylglycerylether sulfonates, methylacyl taurates, paraffin sulfonates, linear alkyl benzene sulfonates, N-acyl glutamates, alkyl sulfosuccinates, alpha sulfo fatty acid esters, alkyl ether carboxylates, alkyl phosphate esters, ethoxylated alkyl phosphate esters, alpha olefin sulphonate, the alkyl ether sulfates (with 1 to 12 ethoxy groups), and mixtures thereof, wherein said surfactants contain C8 to C22 alkyl chain. The anionic surfactant is more preferred wherein said surfactants contain C8 to C18 alkyl chains and wherein the counterion is selected from the group consisting of : Na, K, NH4, N(CH2CH2OH)3.

Some specific examples of preferred surfactants are used in the

Examples herein. Some examples of good mild, lather-enhancing, synthetic detergent surfactants are, e.g., sodium lauroyl sarcosinate, alkyl glyceryl ether sulfonate, sulfonated fatty esters, and sulfonated fatty acids

It is noted that surfactant mildness can be measured by a skin barrier destruction test which is used to assess the irritancy potential of surfactants. In this test the milder the surfactant, the less the skin barrier is destroyed. Skin barrier destruction is measured by the relative amount of radio-labeled water (3H-H2O) 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. These references disclose a mild alkyl glyceryl ether sulfonate (AGS) surfactant based synbar comprising a "standard" alkyl glyceryl ether sulfonate mixture and define the criteria for a "mild surfactant. " Barrier destruction testing is used to select mild surfactants. Some preferred mild synthetic surfactants are disclosed in the above cited Small et al. patent. SOLVENT: The transparent bars of the present invention comprise from about 18 parts to about 37 parts, preferably from about 20 parts to about 32 parts, more preferably from about 20 parts to about 28 parts, of a water soluble organic solvent. The water soluble organic solvent is preferably selected from the group consisting of urea, water soluble organic polyol and mixtures thereof. Urea can be used at a level of 0 to 8 parts, preferable 2 to 7 parts or 3 to 6 parts, but the total level of polyol and urea preferably should not exceed about 37 parts. Preferred water soluble organic polyols are selected from the group consisting of: propylene glycol, dipropylene glycol, butγlene glycol, glycerine and ethylene glycol, 1 ,7-heptane-diol, the mono and polyethylene and propylene glycols of up to 8,000 molecular weight, mono C1 -4 alkyl ethers thereof, sorbitol, glycerol, mono- di- and triethanolamine, 2-amino-1 -butanol, non-reducing sugars, such as sucrose, and mixtures thereof. When used, the preferred non reducing sugar is used at a level of from about 1 part to about 10 parts, preferably from about 2 parts to about 7 parts, by weight of the bar. Unless otherwise specified, the term "sucrose" as used herein includes sucrose, its derivatives, and similar non-reducing sugars and similar polyols which are substantially stable at a soap processing temperature of up to about 210°F (99°C), e.g., trialose, raffinose, and stachyose; and sorbitol, lactitol and maltitol.

The water-soluble organic solvent is a necessary component of the present invention, required for bar transparency. Moreover, the particular level and type of water soluble organic solvent employed are important to optimization of the transparency of the personal cleansing bar.

COMBINATION OF COMPONENTS

In order to obtain a transparent bar, the personal cleansing bars of the present invention must contain certain combined levels of soap and water soluble organic solvent. In particular, in addition to the minimum levels of both solvent and water hereinbefore recited, a minimum combined level of water soluble organic solvent and water of 40 parts by weight of the bar, preferably 45 parts by weight of the bar, is necessary to achieve transparency.

In order to obtain a transparent bar, it is also preferable that the water soluble organic solvent, water and soap be combined within the bar at certain ratios. In particular, the water and the water soluble organic solvent are preferably combined at a ratio of about 2: 1 to 1 :2, most preferably about 1 :1 , to maintain transparency. The soap and the water soluble solvent are preferably combined at a ratio of about 0.8: 1 to about 2:1 , more preferably from about 0.8:1 to 1.5: 1. The ratio of the insoluble soap to soluble soap preferably ranges from about 1.2: 1 to about 2.4: 1 , more preferably from about 1.7:1 to about 2.3:1.

ADDITIVES: The bar soap compositions of the present invention can contain other additives commonly included in toilet bars such as perfumes, other fillers, sanitizing or anti microbial agents, dyes, and the like.

Some preferred bars of this invention contain at least 1 parts of another bar ingredient selected from: moisturizers, colorants, fillers, polymeric skin feel and mildness aids, perfumes, preservatives, and mixtures thereof.

Compatible salt and salt hydrates can be used as fillers. Some preferred salts are sodium chloride, sodium sulfate, disodium hydrogen phosphate, sodium pyrophosphate, sodium tetraborate.

Generally, compatible salts and salt hydrates include the sodium, potassium, magnesium, calcium, aluminum, lithium, and ammonium salts of inorganic acids and small (6 carbons or less) carboxylic or other organic acids, corresponding hydrates, and mixtures thereof, are applicable. The inorganic salts include chloride, bromide, sulfate, metasilicate, orthophosphate, pyrophosphate, polyphosphate, metaborate, tetraborate, and carbonate. The organic salts include acetate, formate, methyl sulfate, and citrate.

Water-soluble amine salts can also be used. Monoethanolamine, diethanolamine, and triethanolamine (TEA) chloride salts are preferred.

Aluminosilicates and other clays are useful in the present invention. Some preferred clays are disclosed in U.S. Pat. Nos. 4,605,509 and 4,274,975, incorporated herein by reference.

Other types of clays include zeolite, kaolinite, montmorillonite, attapulgite, illite, bentonite, and halloysite. Another preferred clay is kaolin.

POUR-MOLDED PROCESS: The transparent cleansing bars of the present invention are prepared by an alcohol-free pour molded process. The process comprises: (A) making a molten mixture of from 18 parts to 35 parts soap; wherein said soap comprises at least 50% insoluble sodium soap; from 14 parts to 32 parts water; from 5 parts to 37 parts synthetic surfactant; and from 18 parts to 37 parts of a water soluble organic solvent; and (B) transferring a unit amount of said molten mixture into a bar forming mold and allowing said molded unit to cool in acquiescent (without mixing or shear) conditions into a mild low smearing transparent personal cleansing bar.

A preferred alcohol free process comprises the following steps:

1 . Mix a mostly insoluble fatty material selected from the group consisting of: triglycerides and fatty acids with a water soluble organic selected from the group consisting of the above polyols and mixtures thereof;

2. Add amphoteric surfactant(s), water, and some salt(s) e.g., sodium chloride with mixing; 3. Raise temperature of the mix of step 2 to 70 °C to 100°C to provide a molten mix;

4. Add enough caustic solution to mix of step 3 saponify the fatty material and to provide a low level of free caustic after saponification/neutralization; cool if needed to prevent boiling; but maintain a molten mix;

5. Add some free fatty acid (at least enough to neutralize all the free caustic) and, optionally, add other synthetic surfactants to mix of step 4.

6. Adjust mix temperature to a maximum of 85 °C; 7. Add other optional ingredients with mixing, maintain 68°C to

85 °C temperature;

8. Pouring molten mix into bar molds or tubes;

9. Condition the mix in the bar molds or tubes to promote crystallization/solidification. Cooling must be conducted under aquiescent conditions at product temperatures below 68°C.

Average cooling rates of 0.1 to 7.0°C per minute are preferred; 10. If tubes are used, the soap plugs are sliced into bar sized plugs;

1 1. Stamp into formed bars and package said formed bars.

A preferred process is a framed bar process. Other processes, such as injection molding, can be used.

EXAMPLES

The following process is used to make the exemplified pour- molded bars. The process comprises the following steps: 1 . Making a molten mixture batch step by step as indicated below.

2. Pouring molten mixture product in bar molds or tubes.

3. Cooling of bars in acquiescent conditions to promote crystallization/solidification. 4. If poured in tubes, the soap plugs are sliced into bar sized plugs.

5. Stamp and package bars. Batch Process

1 . Mix triglycerides (e.g., Hardened Tallow) and/or fatty acids (e.g., Laurie Acid) with water soluble polyol (e.g., Pro^pylene

Glycol) in the Crutcher.

2. Add amphoteric surfactants (e.g., Coco Betaine). water, and salts (e.g., Sodium Chloride) to the crutcher.

3. Raise batch temperature to 70°C to 100°C.

4. Add enough caustic solution (e.g., 30 % Sodium Hydroxide) so that a low level of free caustic remains after saponification/neutralization. If necessary, cool batch to prevent boiling. 5. If necessary, add Free Fattv Acid to the batch.

6. Add other synthetic surfactants (e.g., Sodium Laureth-3 Sulfate⁾ to batch as needed.

7. Adjust batch temperature to a maximum of 85°C.

8. Add other optional ingredients (e.g., Suαar, Perfume) to batch, maintain 68 °C to 85 °C batch temperature.

The temperatures in the process can vary some, e.g., they may vary within 5 degrees C. The key is not to allow the molten mix viscosity to get too high. (e.g. as typically occurs below a temperature of 68°C), and to avoid agitation while cooling the mix. The following Examples illustrate the practice of this invention and are not intended to be limiting. All percentages, parts and ratios herein are by weight unless otherwise specified. The free fatty acids used in the examples are used at the same ratio as the fatty acid soaps. The soaps are made in situ, unless otherwise specified. The levels of soaps are given as a total soap weight percent (wt. %), as well as a bar weight percent (wt. parts).

Examples 1 , 2 and 3 set forth hereinafter are transparent personal cleansing bars of the present invention. These transparent personal cleansing bars exhibit at least marginally acceptable hardness and, in most cases (e.g., Examples 2 and 3), good hardness. Hardness is measured using the cone penetrometer method described in Kacher et al; U.S. Patent 5,340,492; Issued August 23, 1994, herein incorporated by reference. A penetration value of 5 mm or less indicates a very hard bar. A penetration value of from 5 to 10 mm indicates a moderately hard bar. A penetration value of from 10 to 12 mm indicates a somewhat soft bar of marginal acceptance. A penetration value of greater than 1 2 mm indicates a very soft bar which is unacceptable. Penetration values of 10 mm or less are most preferred in terms of hardness. Comparative Examples A, B, C, D and E are personal cleansing bars that fall outside of the claims of the present invention. Comparative Examples B, C and E are not transparent bars. Comparative Examples A and D are unacceptablγ soft.

In Examples 1 -3 and Comparative Examples A-E, "parts other" consists of 1 .5 parts sodium chloride, 1 part free fatty acid, 1 part perfume and 0.1 parts preservative. The polyol is a blend of propylene glycol, dipropylene glycol, glycerine and sucrose. The synthetic surfactant is sodium lauryl ethoxy (3) sulfate.

Example Comparative Example 1 Example 2 Comparativ A e

B

Parts Soap 15 18 32 40

Parts Water 32 32 32 32

Parts Polyol 20 20 23 20

Parts Synthetic Surfacta 29.4 26.4 9.4 5.4

Parts Other 3.6 3.6 3.6 3.6

Ratio of soap to polyol 0.83 1.0 1.52 2.2

Transparent Yes Yes Yes No

Hardness Very Soft somewhat moderately very hard soft hard

Example Comparative Comparative Comparative Exar

C D E Parts Soap 1 8 18 35 35

Parts Water 1 5 35 32 32

Parts Polyol 24.5 32 17 22

Parts Synthetic Surfactan 39.4 1 1.4 12.4 7.4 Parts Other 3.6 3.6 3.6 3.6

Level of Water and Polyo 37.5 65 47 52 Ratio of Water to Polyol 0.67 1.17 2.13 1.6

Transparent? No Yes No Yes

Hardness somewhat very soft moderately moderately soft hard hard EXAMPLE 4

Bar

Inαredient Wt. Darts Soluble Insoluble

Babassu Soap 10.5 9.8 0.7

Hardened Tallow Soap 19.5 0.9 1 8.6

Triple Pressed Fatty Acid 0.5

Propylene Glycol 1 1.0

Dipropylene Glycol 5.5

Glycerine 6.0

Sodium Lauryl Ethoxy

(3) Sulfate 1 2.0

Sodium Lauryl Sulfate 3.0

Coco Betaine 2.0

NaCI 1 .5

Sugar 2.0

Water 24.3

Other 2.2

Totals 100.00 10.7 (35.7 %) 19.3 (64.3

%)

This is a highly preferred bar of the invention. The bar has excellent transparency and lathering properties. The soap was made from a combination of triglγcerides.

EXAMPLE 5

Bar

Inqredient Wt. Darts Soluble Insoluble

Coconut Soap 7.8 6.9 0.9

Hardened Tallow Soap 1 8.2 0.9 1 7.3

Triple Pressed Fatty Acid 1 .0

Propylene Glycol 12.0

Dipropylene Glycol 6.0

Glycerine 6.0

Sodium Lauryl Ethoxy

(3) Sulfate 10.0 Alkylglyceryiether Sulfonate 2.0

Disodium Lauroyl Sulfosuccinate 1.0

Sodium Lauryl Sarcosinate 2.0

Coco Betaine 3.0

Cocoamidopropyl Hydroxysulatine 2.0

NaCI 1.5

Sugar 2.5

Water 22.8

Sodium Citrate 0.5

Other 1.7

Totals 100.00 7.8 (30 %) 18.2 (70 %)

This is another highly preferred bar of the present invention. This bar has excellent transparency, hardness and sudsing characteristics. The bar is also very mild.

EXAMPLE 6

Bar

Inqredient Wt. Darts Soluble Insoluble

Babassu Soap 1 1.2 10.5 0.7

Hardened Tallow Soap 20.8 1.0 19.8

Triple Pressed Fatty Acid 0.5

Propylene Glycol 13.0

Dipropylene Glycol 6.5

Glycerine 6.0

Sodium Lauryl Ethoxy 9.0

(3) Sulfate

Coco Betaine 2.0

NaCI 1.5

Sugar 2.0

Sodium Citrate 1.0

Water 24.3

Other 2.2

Totals 100.00 1 1.5 (35.9 %) 20.5 (64.1 %)

This bar has excellent transparency, sudsing and mildness characteristics.

EXAMPLE 7 Bar

Inqredient Wt. Darts Soluble Insoluble

Cn Soap 12.60 1 1.21 1.39 Hardened Tallow Soap 15.40 0.77 14.63

Triple Pressed FA 2.00

Propylene Glycol 16.81

Glycerine 3.19

Sodium Lauryl Ethoxy (3) Sulfate 12.00

Coco Betaine 2.00

NaCI 1.50

K2SO4 1.00

Sugar 4.50 Water 26.96

Perfume 1.80

Preservative 0.21

Misc. 0.03

Totals 100.00 1 1.98 (43 %) 16.02 (57 %)

This is another preferred bar of the invention. As shown in the "Totals", this bar contains 57 % insoluble soap and 43 % soluble soap. This bar exhibits good transparency properties, has excellent mildness and sudsing characteristics and has good bar structure. This bar was made using triglycerides as the structure former. The lathering synthetic surfactant system of this bar has an equilibrium surface tension of about 29 dynes/cm.

EXAMPLE 8

Inqredient Wt. parts Soluble Insoluble /04360 _r L. i / u ^β**'3 υ-"«-»«

- 19 -

Cn Soap 1 1.20 9.97 1.23

Hardened Tallow Soap 16.80 0.84 15.96

Triple Pressed FA 2.00

Propylene Glycol 1 1.97 Glycerine 8.00

Sodium Lauryl Ethoxy

(3) Sulfate 9.00

Sodium Lauryl Sulfate 3.00

Coco Betaine 2.00 NaCI 1.50

K2SO4 1.00

Sugar 4.50

Water 26.96

Perfume 1.80 Preservative 0.21

Misc. 0.03

Totals 100.00 10.81 (39 %) 17.19

%)

This is another preferred bar of the present invention. It contains 39% soluble soap and 61 % insoluble soap. This bar also exhibits excellent bar performance properties, especially bar hardness. Note that this bar contains 8% Glycerine.

Example 9

Inqredient Wt. parts Soluble Insoluble

Cn Soap 15.53 13.82 1.71

Triple Pressed Soap 16.99 0.85 16.14

Propylene Glycol 25.24

Glycerine 2.09

Sodium Lauryl Ethoxy

(3) Sulfate 1 1.65

Coco Betaine 0.97

NaCI 1.08 ^'

TEA 4.85

Sugar 4.85 Water 1 6.00

Preservative 0.21

Perfume 0.97

Misc. 0.03 Totals 100.00 14.67 (45 %) 17.85

(55 %)

This example has a higher amount of soap and a lower amount of water. This bar was made with a mixture of thglycerides (Coconut Oil) and fatty acids (Triple Pressed Stearic fatty acid).

Example 10

Inqredient Wt. Darts Soluble Insoluble

Cn Soap 13.44 1 1 .96 1 .48

Hardened Tallow Soap 14.56 0.73 13.83

Propylene Glycol 20.00

Glycerine 3.21

Sodium Lauryl Ethoxy

(3) Sulfate 8.00

Coco Betaine 1 .00

NaCI 1 .50

K2SO4 1 .00

Sugar 7.25

Water 27.8

Preservative 0.21

Perfume 1 .00

Misc. 0.03

TToottaallss 110000..0000 1122..6699 ((4455 %%)) 15.31

(55 %)

This is an example of a bar with good bar performance characteristics, but with a lower synthetic surfactant level.

Example 1 1 Inqredient Wt. parts Soluble Insoluble

Laurie Soap 11.00 11.00 0.00

Triple Pressed Soap 16.50 0.82 15.68

Propylene Glycol 22.00

Sodium Lauryl Ethoxy

(3) Sulfate 10.00

Coco Betaine 2.00

TEA 5.00

NaCI 1.00

Urea 5.00

Water 26.2

Preservative 0.21

Perfume 1.00

Misc. 0.06

Totals 100.00 11.82 (43 %) 15.68 (57 %)

This is an example of a bar that is made with only fatty acids. This bar has excellent performance characteristics. This bar is sugar free.

ExamDle 12

Inqredient Wt. Darts Soluble Insoluble

Coconut Soap 10.00 9.00 1.00

Triple Pressed Soap 15.00 0.75 14.25

Triple pressed FA 1.00

Propylene Glycol 20.00

Glycerine 5.00

Sodium Lauryl Ethoxy

(3) Sulfate 10.00

Coco Betaine 1.00

NaCI 1.00

Na2SO4 2.00

Sugar 5.00

TEA 2.00^'

Water 26.76

Preservative 0.21 Perfume 1.00

Misc. 0.03

Totals 100.00 9.75 (39 %) 15.25 (61 %)

This is an example of a bar that is made with only 25 % soap, yet has excellent transparency and good performance characteristics.

Claims

What is Claimed is:

1. A transparent pour molded personal cleansing soap bar characterized in that it comprises:

(A) from 18 parts to 35 parts sodium soap; wherein at least 50% of said sodium soap is insoluble soap;

(B) from 5 parts to 37 parts lathering synthetic surfactant; wherein said lathering synthetic surfactant has a critical micelle concentration equilibrium surface tension between 10 and 50 dynes/cm, as measured at 25°C;

(C) from 14 parts to 32 parts water; and

(D) from 18 parts to 37 parts of a water soluble organic solvent; wherein the combined level of water and water soluble organic solvent within the bar is at least 40 parts.

2. The transparent pour molded personal cleansing soap bar of Claim 1 wherein the water soluble organic solvent is selected from the group consisting of water soluble organic polyols and mixtures of water soluble organic polyols and urea.

3. The transparent pour molded personal cleansing soap bar of Claim 3 and wherein said lathering synthetic surfactant is selected from the group consisting of: acyl isethionates, acyl sarcosinates, alkylglycerylether sulfonates, methylacyl taurates, paraffin sulfonates, linear alkyl benzene sulfonates, N-acyl glutamates, alkyl sulfosuccinates, alpha sulfo fatty acid esters, alkyl ether carboxylates, alkyl phosphate esters, ethoxylated alkyl phosphate esters, alpha olefin sulphonate, the alkyl ether sulfates (with 1 to 12 ethoxy groups), and mixtures thereof, wherein said surfactant contains C8 to C22 alkyl chain and mixtures thereof.

4. The transparent pour molded personal cleansing soap bar of Claim 4 wherein the insoluble soap is selected from the group consisting of sodium palmitate and sodium stearate and higher fatty acids and mixtures thereof.

5. A transparent pour molded personal cleansing soap bar characterized in that it comprises:

(A) from 18 parts to 35 parts sodium soap; wherein at least 50 % of said sodium soap is insoluble soap; (B) from 5 parts to 37 parts lathering synthetic surfactant; wherein said lathering synthetic surfactant has a critical micelle concentration equilibrium surface tension between 10 and 50 dynes/cm, as measured at 25°C;

(C) from 18 parts to 37 parts of a water soluble organic solvent , wherein from 2 to 7 parts of the water soluble organic solvent is urea; and

(D) from 14 parts to 32 parts water; wherein the combined level of water and water soluble organic solvent within the bar ranges is at least 40 parts.

6. The transparent pour molded personal cleansing soap bar of Claim 2 or 5 wherein from 50 % to 87 % by weight of said sodium soap is insoluble soap; and wherein said soap level is 24 parts to 32 parts.

7. The transparent pour molded personal cleansing soap bar of Claim 6 wherein said water soluble organic solvent comprises a polyol selected from the group consisting of: propylene glycol dipropylene glycol, butylene glycol, glycerine and ethylene glycol, 1 ,7-heptane-diol, polyethylene and propylene glycols of up to 8,000 molecular weight, mono-C1-4 alkyl ethers thereof, sorbitol, glycerol, mono- di- and triethanolamine, 2-amino-1- butanol, non-reducing sugars and mixtures thereof.

8. The transparent pour molded personal cleansing soap bar of Claim 7 wherein the ratio of water to water soluble organic solvent within the bar ranges from 2:1 to 1 :2.

9. The transparent pour molded personal cleansing soap bar of Claim 8 wherein the ratio of soap to water soluble organic solvent within the bar ranges from 0.8:1 to 2:1.

10. The transparent pour molded personal cleansing soap bar of Claim 9 wherein the ratio of insoluble soap to soluble soap within the soap mixture ranges from 1.2:1 to 2.4:1.

11. The transparent pour molded personal cleansing soap bar of Claim 10 wherein the bar is alcohol free.