EP3172309B1

EP3172309B1 - Use of specific soap bar composition for enhanced lather in presence of water with high electrolyte concentration

Info

Publication number: EP3172309B1
Application number: EP15733652.0A
Authority: EP
Inventors: Rafael Astolfi; Emiliana Alves Dos Reis Gati; Sergio Roberto Leopoldino; Luiz Felipe Costa Vidigal; Venugopal Vijayakrishnan
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2014-07-22
Filing date: 2015-06-17
Publication date: 2020-10-07
Anticipated expiration: 2035-06-17
Also published as: EA035754B1; ZA201700174B; EA201790006A1; CN106574216A; WO2016012163A1; ES2833234T3; BR112017001260A2; MX2017000839A; EP3172309A1; BR112017001260B1

Description

Background of the invention

Soap bars for cleansing are typically prepared by saponification (e.g., neutralization) of triglyceride/fatty acids. In this saponification process, various fats (e.g., tallow, palms and coconut oil blends) are saponified in the presence of alkali (typically NaOH) to yield alkaline salts of fatty acid (derived from the fatty acid chains forming the glyceride) and glycerol. Glycerol may optionally be extracted with brine (e.g., water with high sodium concentration) to yield dilute fatty acid soap solution containing soap and aqueous phase (e.g., 70% soap and 30% aqueous phase). The soap solution is then typically dried (e.g., to about 12% water) and the remaining mass is milled, plodded and stamped into bars. Alternatively, the soap solution can be cast in to moulds, blisters etc.
The chain length of fatty acid soaps varies depending on starting fat or oil feedstock (for purposes of this specification, "oil" and "fat" are used interchangeably, except where context demands otherwise). Longer chain fatty acid soaps (e.g., C₁₆ palmitic or C₁₈ stearic) are typically obtained from tallow and palm oils, and shorter chain soaps (e.g., C₁₂ lauric) may typically be obtained from, for example, coconut oil or palm kernel oil. The fatty acid soaps produced may also be saturated or unsaturated (e.g., oleic acid).
Typically, longer molecular weight fatty acid soaps (e.g., C₁₄ to C₂₂ soaps) are insoluble and do not generate foam, despite the fact that they can help making the foam generated by other soluble soaps creamier and more stable. Conversely, shorter molecular weight soaps (e.g., C₈ to C₁₂) lather quickly. However, the longer chain soaps are desirable in that they maintain structure and do not dissolve as readily. Unsaturated soaps (e.g., oleic) are soluble and lather quickly, like short-chained soaps, but form a denser, creamier foam, like the longer chained soaps. The particular mixture of chain lengths is critical for establishing lather quality.
Generally, particularly because of the structuring required to produce and maintain a solid soap bar (i.e., structuring is provided by longer chain-length soaps) the production of a pure soap bar having enhanced lathering benefit (e.g., quick lather) is considered extremely difficult.
When synthetic surfactant (e.g., nonionic surfactant) is added to enhance mildness, typically the soap bar must still be predominantly made of long-chain soaps to ensure the bar is well structured and can maintain structure in stamping.
WO 93/04161 (P&G), for example, discloses bars comprising mixtures of soap, C₁₄ - C₂₀ alkyl polyethoxylate nonionic and C₁₆ - C₁₈ acyl isethionate (also a mild surfactant). The soap used comprises at least tallow (longer chain, slower lather) and includes cationic polymeric skin mildness aids and, as moisturizers, free fatty acid.
Foaming is even more difficult in the presence of water containing mono and bivalent electrolyte (e.g., sodium, calcium, magnesium). Such high electrolyte water (also known as hard water or saline water) is common in many parts of the world. As indicated, current mass matter bars do not perform well in saline water due to precipitation of the more soluble soaps (typically short C₈, C₁₀, C₁₂ chain length soap) by divalent salts such as calcium and magnesium salts found in such saline water. In addition, presence of monovalent ions (e.g., sodium) also found in saline water has been observed in lab tests to have negative impact. Specifically, the monovalent ions appear to impact formation of micelles and thereby affect lather formation.
To overcome poor lathering problems generally, references in the art have disclosed use of specially tailored soaps (which involved additional, expensive processing) and/or use of additional, expensive co-actives.
U.S. Patent No. 5,540,852, Kefauver et al. , for example, discloses a mild, lathering personal cleansing soap bar composition comprising from 30 to 85 by wt. tailored fatty acid soap comprising in turn from 50% to 85% of saturated fatty acid soap selected from the group consisting of: myristic, palmitic, and stearic acid soaps. Kefauver fails to disclose specific ratio levels of capric and lauric fatty acid soaps, together with maximum levels of myristic fatty acid, or maximum levels of unsaturated C₁₈ acids other than monounsaturated oleic.
U.S. Patent No. 5,656,579, Chambers et al. discloses a mild toilet soap bar comprising blends of soap with one or more coactives, comprising at least 25% wt. on total actives of lauric acid soaps. Again, Chambers fails to disclose soap bar formulations having maximum amounts of myristic acid soap or of unsaturated C₁₈ other than oleic combined with ratios of capric and lauric fatty acid soaps as claimed in our invention.
The previous attempts to enhance mildness and/or in-use performance are provided by specialized tailoring or use of expensive co-actives.
WO 2013/076047 relates to soap bars having improved lather, with limited amounts of myristic acid, with defined ratios of sum of C₈-C₁₀ fatty acids to C₁₂ fatty acid.
In applicants' co-pending applications 13/625,273 and 13/922,764 , applicants disclose specific blends of fatty acids where ratios of C₈-C₁₀ to C₁₂ soaps are defined and maximum C₁₄ is disclosed.
Applicants have now found that bars similar to those in the co-pending applications (and with differently defined criticalities) can be used to enhance lather when washing in water having high concentration of electrolyte (e.g., bars which have a high defined level of water hardness).
As fresh water represents only a small part of the water in the planet (1.75% frozen and 0.75% from aquifiers, natural lakes, reservoirs, rains), and the rest (97.5%) is saline, it is important to be able to find bars which lather well when using hard water.

Brief Description of Figures

Figure 1 is series of photos showing how lather is defined on a visual scale using qualitative lather volume assessment protocol. The scale applies numerical values to the qualitative determination.

Summary of the invention

More specifically, applicants have now surprisingly found specific compositions and methods for enhancing lather wherein, by rebalancing short chain fatty acids (e.g., ratio of C₁₀ to C₁₂, using no more than a maximum amount of C₁₄, using specific amount and types of unsaturated C₁₈), copious lather can be produced even in water having high concentration of electrolyte (e.g., defined by water hardness value greater than about 25 °FH, preferably greater than about 50 °FH, preferably greater than about 75 °FH; water hardness of seawater is about 635 °FH.

Detailed description of the invention

The present invention relates to the use of a soap bar composition which enhances lather when used with water having high concentration of electrolyte (i.e. having hardness of greater than about 25 °FH). The bar compositions comprise:

a) a fatty acid soap blend in an amount of 30 to 90% by wt. of the soap bar wherein:
1. i. the ratio of C₁₀ to C₁₂ fatty acid is about 0.5:1.0 to about 1.5:1.0, preferably from about 0.75:1 to 1.25:1, more preferably about 1:1; and capric and lauric acids are present in an amount of at least 3% by weight of the bar composition;
2. ii. C₁₄ fatty acid is present at 0 to about 3.5% maximum, preferably about 0.1 to about 3.0% by wt. bar composition;
3. iii. oleic acid is present at about 25% to about 35% of bar composition;
4. iv. amount of unsaturated C₁₈ fatty acid other than oleic is 0 to about 10% maximum, preferably 0 to about 5%;
b) about 0.1 to about 15% by wt. of composition polyol;
c) about 0.1 to about 25% by wt., preferably 0.1 to 15% by wt. of composition mineral or organic particles; and
d) about 10% to 30%, preferably 13 to 20% water.

The invention relates to the use of a bar for enhancing lather when washing in water having high amount of dissolved salt, particularly divalent salts such as calcium and magnesium and monovalent salts such as sodium (i.e., high electrolyte containing water). Lather is enhanced in water having hardness of greater than about 25 °FH, more preferably greater than about 50g °FH. The use comprises lathering in water of noted hardness with bars having the composition noted above to achieve enhanced lather (e.g., improvement of greater than about 30% in lather) when compared to the lather formed using bars in which the ratio of C₁₀ to C₁₂, the maximum amounts of C₁₄, and the maximum amounts of unsaturated C₁₈ other than oleic are outside those claimed above. Specifically, the criteria noted must be used.
When using a bar having ratio of palm oil plus palm oil stearine to palm kernel oil (PKO) of 60:40, bars which have been tailored ("designed") so that chain length distributions are as noted above will have foam values (measured in millimeters using SITA® foam tester, e.g., SITA® Foam Tester R-2000; or in quantitative appraisal test defined in protocol) which are greater than about 30%, preferably greater than about 40% higher than bar with same 60:40 ratio of the same oils but where the ratios of chain lengths and maximum values of certain fatty acids (C₁₄; unsaturated C₁₈ other than oleic) are not as specifically claimed in this invention.

Soap bar composition

The present invention relates to the use of extruded or melt cast personal washing bars that comprise specific levels and ratios of various fatty acid soaps; optionally one or more added polyols, polymers, organic and inorganic adjuvant materials, electrolytes, benefit agents and other minor ingredients and the remainder of water. These components of the bar composition that are used to manufacture and evaluate the bars are described below. The bar compositions used in the invention are capable of being manufactured by processes that generally involve the extrusion forming of ingots or billets, and stamping or molding of these billets into individual tablets, cakes, or bars and alternatively the products can be obtained by the melt cast process.

Fatty acid soap blend

The fatty acid soaps, other surfactants and in fact all the components of the bar should be suitable for routine contact with human skin and preferably yield bars that are high lathering. The bars yield superior lather even when washing in water having high concentration of divalent and monovalent salts. This lather is compared to lather generated by bars formed from same oil base but in which fatty acids have not been tailored as defined. Improvement in lather is greater than about 30%, preferably greater than about 40% compared to bar not meeting limitation (see comparative bar in Example). This is true in either quantitative test defined in protocol or in quantitative SITA® foam test machinery data obtained as also defined in protocol.
The soap bar composition providing improved lather comprises fatty acid blend soap preferably in an amount of 30 to 85% by wt. of the soap bar. More preferably, the fatty acid blend comprises a fatty acid blend in an amount of 40 to 80% by wt. of the soap bar. Most preferably, the fatty acid blend comprises a fatty acid blend in an amount of 45 to 78% by wt. of the soap bar.
The fatty acid blend comprises one or more surfactants. The preferred type of surfactant is fatty acid soap. The term "soap" is used herein in its popular sense, i. e., the alkali metal or alkanol ammonium salts of aliphatic, alkanes, or alkene monocarboxylic acids. Sodium, potassium, magnesium, mono-, di- and tri-ethanol ammonium cations, or combinations thereof, are the most suitable for purposes of this invention. In general, sodium soaps are used in the compositions of this invention, but up to about 15% of the soap may be potassium, magnesium or triethanolamine soaps. The soaps useful herein are the well known alkali metal salts of natural or synthetic aliphatic (alkanoic or alkenoic) acids having about 8 to about 24 carbon atoms. They may be described as alkali metal carboxylates of saturated or unsaturated hydrocarbons having about 8 to about 24 carbon atoms. Alkali metal salts are preferred.
The fatty acid blend is made from fatty acids that may be different fatty acids, typically fatty acids containing fatty acid moieties with chain lengths of from C₈ to C₂₄. The fatty acid blend may also contain relatively pure amounts of one or more fatty acids. Suitable fatty acids include, but are not limited to, butyric, caproic, caprylic, capric, lauric, myristic, myristelaidic, pentadecanoic, palmitic, palmitoleic, margaric, heptadecenoic, stearic, oleic, linoleic, linolenic, arachidic, gadoleic, behenic and lignoceric acids and their isomers. It is preferred to minimize or eliminate amount of butyric and caproic. In a preferred embodiments, the fatty acid blend has fatty acids with fatty acids moiety chains length of 10 (capric acid) and 12 (lauric acid) carbon atoms used in specifically defined ratios. In preferred embodiments, the fatty acid blend has low levels of fatty acid with saturated fatty acid moiety chain length of 14 carbon atoms (myristic acid).
The fatty acid blend of the present invention comprises relatively high amounts (i.e. at least 3 %, preferably at least 10% by wt. bar composition) of capric and lauric acids wherein ratio of C₁₀ to C₁₂ is in a defined range. More particularly, C₈ to C₁₄ fatty acids should comprise about 10% to about 32% by wt. of composition (C₁₄ alone comprises no more than about 3.5% by wt. of composition); C₁₆ to C₁₈ long saturated chain should comprise about 15% to 55% by wt. composition; and long unsaturated C₁₈ (e.g., oleic) should comprise about 25 to 35% by wt. of composition (unsaturated C₁₈ other than oleic comprises 5% by wt. or less). Together, there criticalities ensure superior lather in high electrolyte water relative to bar with the same oil base where criticalities (e.g., tailoring or designing of chain lengths) are not met.
The proportion of capric acid to lauric acid ranges from 0.5 to 1 to 1.5 to 1. Preferably, ratio is 0.75 to 1 to 1.25 to 1.
The fatty acids may be eventually in the form of free fatty acids, preferably in an amount not higher than 5% of the fatty acid soap blend.

Organic and Inorganic adjuvant materials

The total level of the adjuvant materials used in the bar composition should be in an amount not higher than 50% by wt. of the soap bar composition.
Suitable starchy materials which may be used include natural starch (from corn, wheat, rice, potato, tapioca and the like), pregelatinzed starch, various physically and chemically modified starch and mixtures thereof. By the term natural starch is meant starch which has not been subjected to chemical or physical modification - also known as raw or native starch.
A preferred starch is natural or native starch from maize (corn), cassava, wheat, potato, rice and other natural sources of it. Raw starch with different ratio of amylose and amylopectin: e.g. maize (25% amylose); waxy maize (0%); high amylose maize (70%); potato (23%); rice (16%); sago (27%); cassava (18%); wheat (30%) and others. The raw starch can be used directly or modified during the process of making the bar composition such that the starch becomes gelatinized, either partially or fully gelatinized.
Another suitable starch is pre-gelatinized which is starch that has been gelatinized before it is added as an ingredient in the present bar compositions. Various forms are available that will gel at different temperatures, e.g., cold water dispersible starch. One suitable commercial pre-gelatinized starch is supplied by National Starch Co. (Brazil) under the trade name FARMAL® CS 3400 but other commercially available materials having similar characteristics are suitable.

Poly-ol

Another organic adjuvant could be a polyol or mixture of polyols. Polyol is a term used herein to designate a compound having multiple hydroxyl groups (at least two, preferably at least three) which is highly water soluble, preferably freely soluble, in water.
Many types of polyols are available including: relatively low molecular weight short chain polyhydroxy compounds such as glycerol and propylene glycol; sugars such as sorbitol, manitol, sucrose and glucose; modified carbohydrates such as hydrolyzed starch, dextrin and maltodextrin, and polymeric synthetic polyols such as polyalkylene glycols, for example polyoxyethylene glycol (PEG) and polyoxypropylene glycol (PPG).
Especially preferred polyol are glycerol, sorbitol and their mixtures.
The level of polyol is critical in forming a thermoplastic mass whose material properties are suitable for both high speed manufacture (300-400 bars per minute) and for use as a personal washing bar. It has been found that when the polyol level is too low, the mass is not sufficiently plastic at the extrusion temperature (e.g., 40o C to 45o C) and the bars tend to exhibit higher mushing and rates of wear. Conversely, when the polyol level is too high, the mass becomes too soft to be formed into bars by high speed at normal process temperature.
The bars used in the invention comprise 0.1 to to 15% by wt. polyol. Preferred polyols, as noted, include glycerol, sorbitol and mixtures thereof.
The adjuvant system may optionally include insoluble particles comprising one or a combination of materials. By insoluble particles is meant materials that are present in solid particulate form and suitable for personal washing. Preferably, there are mineral (e.g., inorganic) or organic particles.
The insoluble particles should not be perceived as scratchy or granular and thus should have a particle size less than 300 microns, more preferably less than 100 microns and most preferably less than 50 microns.
Preferred inorganic particulate material includes talc and calcium carbonate. Talc is a magnesium silicate mineral material, with a sheet silicate structure and a composition of Mg3Si4 (OH)22, and may be available in the hydrated form. It has a plate-like morphology, and is essentially oleophilic/hydrophobic, i.e., it is wetted by oil rather than water.
Calcium carbonate or chalk exists in three crystal forms: calcite, aragonite and vaterite. The natural morphology of calcite is rhombohedral or cuboidal, acicular or dendritic for aragonite and spheroidal for vaterite.
Commercially, calcium carbonate or chalk known as precipitated calcium carbonate is produced by a carbonation method in which carbon dioxide gas is bubbled through an aqueous suspension of calcium hydroxide. In this process the crystal type of calcium carbonate is calcite or a mixture of calcite and aragonite.
Examples of other optional insoluble inorganic particulate materials include alumino silicates, aluminates, silicates, phosphates, insoluble sulfates, borates and clays (e.g., kaolin, china clay) and their combinations.
Organic particulate materials include: insoluble polysaccharides such as highly crosslinked or insolubilized starch (e.g., by reaction with a hydrophobe such as octyl succinate) and cellulose; synthetic polymers such as various polymer lattices and suspension polymers; insoluble soaps and mixtures thereof.
Bar compositions preferably comprise 0.1 to 25% by wt. of bar composition, preferably 5 to 15 by wt. of these mineral or organic particles.

Water

Bars of the invention comprise 10 to 30% by wt., preferably 13 to 20% by wt. water.

Optional ingredients

Synthetic surfactants:

The bar compositions can optionally include non-soap synthetic type surfactants (detergents) - so called syndets. Syndets can include anionic surfactants, nonionic surfactants, amphoteric or zwitterionic surfactants and cationic surfactants.
The level of synthetic surfactant present in the bar is generally less than 25%, preferably less than 15%, preferably up to 10%, and most preferably from 0 to 7% based on the total weight of the bar composition.
The anionic surfactant may be, for example, an aliphatic sulfonate, such as a primary alkane (e.g., C₈-C₂₂) sulfonate, primary alkane (e.g., C₈-C₂₂) disulfonate, C₈-C₂₂ alkene sulfonate, C₈-C₂₂ hydroxyalkane sulfonate or alkyl glyceryl ether sulfonate (AGS); or an aromatic sulfonate such as alkyl benzene sulfonate. Alpha olefin sulfonates are another suitable anionic surfactant.
The anionic may also be an alkyl sulfate (e.g., C₁₂-C₁₈ alkyl sulfate), especially a primary alcohol sulfate or an alkyl ether sulfate (including alkyl glyceryl ether sulfates).
The anionic surfactant can also be a sulfonated fatty acid such as alpha sulfonated tallow fatty acid, a sulfonated fatty acid ester such as alpha sulfonated methyl tallowate or mixtures thereof.
The anionic surfactant may also be alkyl sulfosuccinates (including mono- and dialkyl, e.g., C₆-C₂₂ sulfosuccinates); alkyl and acyl taurates, alkyl and acyl sarcosinates, sulfoacetates, C₈-C₂₂ alkyl phosphates and phosphates, alkyl phosphate esters and alkoxyl alkyl phosphate esters, acyl lactates or lactylates, C₈-C₂₂ monoalkyl succinates and maleates, sulphoacetates, and acyl isethionates.
Another class of anionics is C₈ to C₂₀ alkyl ethoxy (1-20 EO) carboxylates.
Another suitable anionic surfactant is C₈-C₁₈ acyl isethionates. These esters are prepared by reaction between alkali metal isethionate with mixed aliphatic fatty acids having from 6 to 18 carbon atoms and an iodine value of less than 20. At least 75% of the mixed fatty acids have from 12 to 18 carbon atoms and up to 25% have from 6 to 10 carbon atoms. The acyl isethionate may also be alkoxylated isethionates
Acyl isethionates, when present, will generally range from about 0.5% to about 25% by weight of the total composition.
In general, the anionic component will comprise the majority of the synthetic surfactants used in the bar composition.
Amphoteric detergents which may be used in this invention include at least one acid group. This may be a carboxylic or a sulphonic acid group. They include quaternary nitrogen and therefore are quaternary amido acids. They should generally include an alkyl or alkenyl group of 7 to 18 carbon atoms. Suitable amphoteric surfactants include amphoacetates, alkyl and alkyl amido betaines, and alkyl and alkyl amido sulphobetaines.
Amphoacetates and diamphoacetates are also intended to be covered in possible zwitterionic and/or amphoteric compounds which may be used.
Suitable nonionic surfactants include the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols or fatty acids, with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Examples include the condensation products of aliphatic (C₈-C₁₈) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergent compounds include long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides.
The nonionic may also be a sugar amide, such as alkyl polysaccharides and alkyl polysaccharide amides.
Examples of cationic detergents are the quaternary ammonium compounds such as alkyldimethylammonium halides.
Other surfactants which may be used are described in U.S. Pat. No. 3, 723,325 to Parran Jr. and "Surface Active Agents and Detergents" (Vol. I & II) by Schwartz, Perry & Berch, both of which is also incorporated into the subject application by reference.

Finishing adjuvant materials:

These are ingredients that improve the aesthetic qualities of the bar especially the visual, tactile and olefactory properties either directly (perfume) or indirectly (preservatives). A wide variety of optional ingredients can be incorporated in the bar composition. Examples of adjuvants include but are not limited to: perfumes; opacifying agents such as fatty alcohols, ethoxylated fatty acids, solid esters, and TiO₂; dyes and pigments; pearlizing agent such as TiO₂ coated micas and other interference pigments; plate like mirror particles such as organic glitters; sensates such as menthol and ginger; preservatives such as dimethyloldimethylhydantoin (Glydant XL1000), parabens, sorbic acid and the like; anti-oxidants such as, for example, butylated hydroxytoluene (BHT); chelating agents such as salts of ethylene diamine tetra acetic acid (EDTA) and trisodium etridronate; emulsion stabilizers; auxiliary thickeners; buffering agents; and mixtures thereof.
The level of pearlizing agent should be between about 0.1% to about 3%, preferably between 0.1% and 0.5% and most preferably between about 0.2 to about 0.4% based on the total weight of the bar composition.

Skin benefit agents:

A particular class of optional ingredients highlighted here is skin benefit agents included to promote skin and hair health and condition. Potential benefit agents include but are not limited to: lipids such as cholesterol, ceramides, and pseudoceramides; antimicrobial agents such as TRICLOSAN; sunscreens such as cinnamates; other types of exfoliant particles such as polyethylene beads, walnut shells, apricot seeds, flower petals and seeds, and inorganics such as silica, and pumice; additional emollients (skin softening agents) such as long chain alcohols and waxes like lanolin; additional moisturizers; skin-toning agents; skin nutrients such as vitamins like Vitamin C, D and E and essential oils like bergamot, citrus unshiu, calamus, and the like; water soluble or insoluble extracts of avocado, grape, grape seed, myrrh, cucumber, watercress, calendula, elder flower, geranium, linden blossom, amaranth, seaweed, gingko, ginseng, carrot; impatiens balsamina, camu camu, alpina leaf and other plant extracts such as witch-hazel, and mixtures thereof.
The composition can also include a variety of other active ingredients that provide additional skin (including scalp) benefits. Examples include anti-acne agents such as salicylic and resorcinol; sulfur-containing D and L amino acids and their derivatives and salts, particularly their N-acetyl derivatives; anti-wrinkle, anti-skin atrophy and skin-repair actives such as vitamins (e.g., A,E and K), vitamin alkyl esters, minerals, magnesium, calcium, copper, zinc and other metallic components; retinoic acid and esters and derivatives such as retinal and retinol, vitamin B3 compounds, alpha hydroxy acids, beta hydroxy acids, e.g. salicylic acid and derivatives thereof; skin soothing agents such as aloe vera, jojoba oil, propionic and acetic acid derivatives, fenamic acid derivatives; artificial tanning agents such as dihydroxyacetone; tyrosine; tyrosine esters such as ethyl tyrosinate and glucose tyrosinate; skin lightening agents such as aloe extract and niacinamide, alpha-glyceryl-L-ascorbic acid, aminotyroxine, ammonium lactate, glycolic acid, hydroquinone, 4 hydroxyanisole, sebum stimulation agents such as bryonolic acid, dehydroepiandrosterone (DHEA) and orizano; sebum inhibitors such as aluminum hydroxy chloride, corticosteroids, dehydroacetic acid and its salts, dichlorophenyl imidazoldioxolan (available from Elubiol); anti-oxidant effects, protease inhibition; skin tightening agents such as terpolymers of vinylpyrrolidone, (meth)acrylic acid and a hydrophobic monomer comprised of long chain alkyl (meth)acrylates; anti-itch agents such as hydrocortisone, methdilizine and trimeprazine hair growth inhibition; 5-alpha reductase inhibitors; agents that enhance desquamation; anti-glycation agents; anti-dandruf agents such as zinc pyridinethione; hair growth promoters such as finasteride, minoxidil, vitamin D analogues and retinoic acid and mixtures thereof.

Electrolyte

The soap bars may include 0.5 wt% to 5 wt% electrolyte. Preferred electrolytes include chlorides, sulphates and phosphates of alkali metals or alkaline earth metals. Without wishing to be bound by theory it is believed that electrolytes help to structure the solidified soap mass and also increase the viscosity of the molten mass by common ion effect. Comparative soap bars without any electrolyte were found to be softer. Sodium chloride and sodium Sulphate are the most preferred electrolyte, more preferably at 0.6 to 3.6 wt%, and most preferably at 1.0 to 3.6 wt%.

Polymers

The soap bars may include 0.1 to 5 wt % of a polymer selected from acrylates or cellulose ethers. Preferred acrylates include cross-linked acrylates, polyacrylic acids or sodium polyacrylates. Preferred cellulose ethers include carboxymethyl celluloses or hydroxyalkyl celluloses. A combination of these polymers may also be used, provided the total amount of polymers does not exceed 5 wt%.

Acrylates

Preferred bars include 0.1 to 5% acrylates. More preferred bars include 0.15 to 3% acrylates. Examples of acrylate polymers include polymers and copolymers of acrylic acid crosslinked with polyallylsucrose as described in US Patent 2,798,053 which is herein incorporated by reference. Other examples include polyacrylates, acrylate copolymers or alkali swellable emulsion acrylate copolymers (e.g., ACULYN® 33 Ex. Rohm and Haas; CARBOPOL® Aqua SF-1 Ex. Lubrizol Inc.), hydrophobically modified alkali swellable copolymers (e.g., ACULYN® 22, ACULYN® 28 and ACULYN® 38 ex. Rohm and Haas). Commercially available crosslinked homopolymers of acrylic acid include CARBOPOL® 934, 940, 941, 956, 980 and 996 carbomers available from Lubrizol Inc. Other commercially available crosslinked acrylic acid copolymers include the CARBOPOL® Ultrez grade series (Ultrez® 10, 20 and 21) and the ETD series (ETD 2020 and 2050) available from Lubrizol Inc.
CARBOPOL® Aqua SF-1 is a particularly preferred acrylate. This compound is a slightly cross-linked, alkali-swellable acrylate copolymer which has three structural units; one or more carboxylic acid monomers having 3 to 10 carbon atoms, one or more vinyl monomers and, one or more mono- or polyunsaturated monomers.

Cellulose ethers

Preferred bars include 0.1 to 5% cellulose ethers. More preferred bars include 0.1 to 3% cellulose ethers. Preferred cellulose ethers are selected from alkyl celluloses, hydroxyalkyl celluloses and carboxyalkyl celluloses. More preferred bars include hydroxyalkyl celluloses or carboxyalkyl celluloses and particularly preferred bars include carboxyalkyl cellulose.
Preferred hydroxyalkyl cellulose includes hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and ethyl hydroxyethyl cellulose. Preferred carboxyalkyl cellulose includes carboxymethyl cellulose. It is particularly preferred that the carboxymethyl cellulose is in form of sodium salt of carboxymethyl cellulose.

Wax and Polyalkyleneglycols

Preferred wax includes paraffin wax and microcrystalline wax. When polyalkyleneglycols are used, preferred bars may include 0.01 to 5 wt% Polyalkyleneglycols, more preferably 0.03 to 3 wt% and most preferably 0.5 to 1 wt%. Suitable examples include polyethyleneglycol and polypropyleneglycol. A preferred commercial product is POLYOX® sold by The Dow Chemical Company.
A preferred composition of the invention comprises (by wt.):

1) 30-85% soap, preferably sodium soap;
2) 0.1 to 20% polyol, preferably glycerine, sorbitol or mixture;
3) 0.1 to 25% particles; and
4) 10-30% water.

In this preferred embodiment:

a) ratio of C₁₀ to C₁₂ fatty acid is 0.5 to 1.0 to 1.5 to 1.0;
b) C₁₄ is used at less than or equal to 3.5% by wt.;
c) oleic acid is 26-34% by wt.; and
d) C₁₈ other than oleic is 0 to 8% by wt.

In a preferred embodiment, bars are prepared using mixture of palm oil (PO), palm oil stearine (POS), and palm kernel oil (PKO) and ratio of (PO plus POS) to PKO is 75:25, preferably 60:40.
The invention relates to the use of a bar composition for enhancing lather when washing in high electrolyte containing water which comprises applying to skin or suitable substrate bar compositions as defined above and wherein enhanced lather is relative to bar produced from same types and ratios of oils (e.g., 60:40 (PO plus POS/PKO), but where specific fatty acid blends are not tailored to meet specific criteria defined by this invention.
The increase in foam of bars of the specification (tested in water of defined hardness) is greater than about 30%, preferably greater than about 40% as measured in mL by SITA® foam tester or in quantitative test also defined in protocol, compared to bars outside the invention (e.g., not tailored as defined by invention).
The invention relates to of the use of a bar composition for enhancing lather when washing in water having water hardness greater than about 25 French hardness (FH), preferably greater than about 50 French Hardness, more preferably greater than about 75 FH, even more preferably greater than about 100 FH which method comprises applying to skin or other substrate bar compositions defined by compositions of claim 1 wherein enhanced lather is relative to bar product from the same type and ratios of oils but where specific fatty acid blends do not fall with C₁₀:C₁₂ ratios, minimal C₁₄ amounts and minimal unsaturated C₁₈ other than oleic amounts defined.

Protocols and Examples

QUANTITATIVE LATHER VOLUME ASSESSMENT PROTOCOL:

1. Introduction

The amount of lather generated by a soap bar is an important parameter affecting consumer preference. The lather volume test described herein gives a measure of lather generation under standard conditions, thus allowing objective comparison of different soap formulations.

2. Principle

Lather is generated by trained technicians using a standardised method. The lather is collected and its volume measured.

3. Equipment

Washing up bowl	-	1 per operator capacity 10 litres
Soap drainer dishes	-	1 per sample
Surgeons' rubber gloves	-
Tall cylindrical glass beaker	-	400 mL, 25 mL graduated (Pyrex n°1000)
Thermometer	-
Glass rod	-

Procedure

i. Tablet pre-treatment:
Wearing a surgeon's rubber gloves which have previously been washed in plain soap, wash down all test tablets (e.g., bars) at least 10 minutes before starting the test sequence. This is best done by twisting them about 20 times through 180° (i.e., a half turn) under running water (at about 30°C).
ii. Place about 5 litres of water of known hardness and at a specified temperature in a bowl. Typically, water temperature is about 30°C and kept constant for a given series of assessments. Change the water after each bar of soap has been tested.
iii. Take up the tablet, dip it in the water and remove it. Twist the tablet 15 times, between the hands, through 180°. Place the tablet on the soap dish.
iv. The lather is generated by the soap remaining on the gloves.

Stage 1:	Rub one hand over the other hand (two hands on same direction) 10 times in the same way.
Stage 2:	Grip the right hand with the left, or vice versa, and force the lather to the tips of the fingers.

This operation is repeated five times.
Repeat Stages 1 and 2.
Place the lather in the beaker.
v. Repeat the whole procedure of lather generation from paragraph iii, twice more, combining all the lather in the beaker.
vi. Stir the combined lather gently to release large pockets of air. Read and record the volume.

Data analysis is carried out by two way analysis of variance, followed by Turkey's Test.

MEASURING PROTOCOL USING SITA® FOAM CREATOR R2000 APPARATUS (QUANTITATIVE):

1. Set the parameters on the equipment as:
1. a) Volume: 250mL
2. b) Bath Temperature: 37°C
3. c) Measurements: 99
4. d) Speed: 800 revolutions per minute
5. e) Shaking time: 20 seconds
2. Prepare a 10% wt solution of the soap in simulated seawater. (The simulated seawater composition is defined in the Table at Example 2 and has French Hardness of 635 FH).
3. Press start button and let the machine work.

QUALITATIVE LATHER VOLUME ASSESSMENT PROTOCOL:

1- Wet the hands and wet the bar;
2- Spin the bar 15 times outside the water;
3- Put bar in the soap dish and gather the lather formed;
4- Clasp hands 3 times and gather the lather formed;
5- Rub the hands 3 times in the back and forth movement and gather the lather formed;
6- Clasp hands 3 times and gather the lather formed;
7- Rub the hands 3 times in the back and forth movement and gather the lather formed;
8- Clasp hands 3 times and gather all the lather formed;
9- Evaluate lather volume according to a visual scale where determination is on visual scale as seen in Figure 1 (e.g., tested composition having no foam is judged to have level of zero, and composition with maximum foam is judged to have level of ten).

Examples

Solid moisturizing personal wash bars were prepared with different percentages of fatty acids in accordance with the formulations herein below.
The fatty acids used to prepare the formulations are supplied by Cosmoquimica under the commercial Name of Edenor® C8 98/100 (Caprilic acid); Edenor® C10 98/100 (Capric acid); Edenor® C12 98/100 (Lauric acid); Edenor® C14 98/100 (Myristic acid); Edenor® C16 98/100 (Palmitic acid); Edenor® C18 98/100 (Stearic acid); Edenor® C18:1 98/100 (Oleic acid).
Other fatty acids possible suppliers are Químico Anastácio, Emery Oleochemicals and Aboissa Óleos Vegetais.

Example 1 and Comparative A and B

Various fatty acid soap distributions are set forth in Table 1:

Table 1

Composition	Comparative A (blending conventional oils)	Comparative B (blending conventional oils)	Example 1 (optimized blending)
C₈ caprylic	0.92	1.53	2.00
C₁₀ capric	0.70	1.32	14.00
C₁₂ lauric	10.12	19.45	14.00
C₁₄ myristic	4.15	6.93	2.00
C_14:1 myristelaidic	0.00	0.00	0.00
C₁₅ pentadecanoic	0.05	0.04	0.00
C₁₆ palmitic	41.87	29.16	17.00
C_16:1 palmitoleic	0.11	0.10	0.00
C₁₇ margaric	0.10	0.07	0.00
C_17:1 heptadecenoic	0.00	0.00	0.00
C₁₈ stearic	5.15	4.25	17.00
C_18:1 oleic	29.61	30.11	32.00
C_18:2 linoleic	6.89	6.73	2.00
C_18:3 linolenic	0.13	0.11	0.00
C₂₀ arachidic	0.09	0.04	0.00
C_20:1 gadoleic	0.00	0.00	0.00
C₂₂ behenic	0.11	0.16	0.00
C₂₄ lignoceric	0.00	0.00	0.00
Others	0.00	0.00	0.00
Iodine value(gl₂/100g)*	39.54	39.65	32.00
Total short saturated (%)	15.90	29.23	32.00
Total unsaturated (%)	36.74	37.05	34.00
Total long saturated (%)	47.36	33.71	34.00

Palm oil	40	58	--
Palm oil stearine	40	2	--
PKO	20 (conventional 80/20 bar)	40 (conventional 60/40 bar)	-(60/40 as tailored by invention)

Appraisal Results** when using seawater	Comparative A	Comparative B	Example 1
Lather value (ml) (Quantitative test)	50	56	238
Qualitative scale (0-10)	0-2	0-2	8-10

* grams of iodine per 100g.
** Seawater had hardness as indicated in Table noted below in Example 2.

The results show that, rather than by increasing amount of natural oils (Comparative B) where more palm kernel oil (PKO) was used, if instead the amount of short chain oils (C₈, C₁₀, C₁₂, C₁₄) was rebalanced, copious lather was produced even using extreme water conditions (e.g., where amount of mono and divalent salts per liter of water >3 g/l, greater than 6 g/L or more). Specifically, the amounts of C₁₀ and C₁₂ were increased (and kept within tightly bound ratios as per the claims) while minimizing the amount of C₁₄ and unsaturated C₁₈ other than oleic. As indicated, in the rebalanced composition (Example 1), lather volume was 238 ml (versus 50 or 56 in comparatives A and B) and, on a qualitative scale, trained panelists noted scores of 8-10. Example 2

Hardness level of seawater and other water is noted below:

Table 1 of water composition

	18° FH*	Brackish Africa	Brackish India	Seawater
Sodium chloride	Traces	1.82	3.24	24.1
Magnesium chloride	0.09	1.23	0.3	5.1
Sodium sulphate	0	0	0	4.0
Calcium chloride	0.198	3.47	0.41	1.1
Potassium chloride	0	0	0	0.8
Hardness	18	442	69	635

*FH = French hardness

As indicated, seawater was used for results of Example 1. The example also shows high hardness level (greater than 50, greater than 100) of brackish water in various countries.
Applicants also tested (in seawater using SITA® protocol) what was maximum lather for individual C₈, C₁₀, C₁₂, C₁₄ chain lengths; for composition of Example 1; and composition of Comparative B, and results are set forth below. Table 2

Carbon chain Maximum lather volume (mL)

C₈ 440

C10 390

C12 440

C14 150

Ideal Composition (C10-C12) 1:1 435

Conventional 60/40 270
It can be clearly seen that salt water (e.g., sodium ions) have strong negative impact on foam with C₁₄ chain length being particularly affected. It can also clearly be seen that a composition, where shorter chain length is optimized relative to conventional bars, had far superior foam.

Example 3

Applicants also took the formulation with optimized blending (Example 1) and diluted the compositions to varying ratios. By "diluted" we mean there is higher amount of longer chain fatty acids which, as we see, would be expected to foam less. The diluted compositions were tested in the laboratory and in a SITA tester and results are set forth below:

Table 2

	Qualitative Scale (0-10 scale)	Appraisal (mL) (Quantitative test)	SITA Foam Tester (mL)
80/20 bar, but "designed" to have greater level of shorter chain	4	108	300
"Designed" 70/30 bar	8	197	415
"Designed" 60/40 bar	9	238	425
Conventional 60/40 blend	2	56	275

As can be noted, the "designed" bars show superior performance, even when diluted to great extent (80/20). By using greater amount of shorter chain then conventional bars, unexpectedly superior foam is retained.

Claims

Use of a bar composition for enhancing lather when washing in water having water hardness greater than 25 °French Hardness, wherein said bar comprises:
a) 30-90% by wt. bar composition alkali metal or alkanol ammonium salt fatty acid soap wherein:
(i) ratio of C₁₀ chain length fatty acid soap to C₁₂ chain length fatty acid soap is about 0.5:1.0 to about 1.5:1.0, wherein capric and lauric acids are present in an amount of at least 3% by wt. of the bar composition;

(ii) wherein C₁₄ chain length fatty acid is 0 to about 3.5% maximum by wt. of bar composition;

(iii) wherein amount of unsaturated C₁₈ is about 25 to 35% by wt. of bar composition; and

(iv) wherein amount of unsaturated C₁₈ fatty acid other than oleic is 0 to about 5% maximum by wt. of bar composition,

b) about 0.1 to about 15% by wt. of bar composition polyol;

c) about 0.1 to 25% by wt. mineral or organic particles; and

d) about 10% to 30% by weight water.
Use of a bar composition according to claim 1 wherein ratio of C₁₀ to C₁₂ is about 1:1.
Use of a bar composition according to claim 1 or 2 wherein amount of C₁₄ is about 0.1 to about 3.0% by wt.
Use of a bar composition according to any one of the preceding claims, wherein said polyol is selected from the group consisting of glycol, sorbitol and mixtures thereof.
Use of a bar composition according to any one of the preceding claims, wherein the bar is produced from a combination of palm oil (PO), palm oil stearine (POS) and palm kernel oil (PKO) and ratio of (PO and POS) to PKO is about 60:40 to about 80:20.