MXPA98008031A - Bar composition that comprises non-ionic polymeric surfactants as agents that improve lasuavi - Google Patents

Abstract

The present invention is directed to synthetic stick compositions, where it has been found that relatively small amounts of hydrophobically-modified modified polyalkylene glycol nonionic polymer improves the smoothness of stick compositions without sacrificing processability and foaming property.

Description

BAR COMPOSITION THAT INCLUDES NON-IONIC POLYMERIC SURFACTANTS AS AGENTS THAT IMPROVE THE SMOOTHNESS FIELD OF THE INVENTION The present invention relates to synthetic stick compositions (ie, sticks in which at least some of the fatty acid soap has been replaced by synthetic surfactants, such as synthetic anionic surfactants.

BACKGROUND OF THE INVENTION Traditionally, soap has been used as a skin cleanser. Without considering its many advantages (for example, cheap, easy to manufacture in bars, has good foaming properties), soap is a very aggressive chemical compound. It often results in an irritated and cracked skin from the use of soap, especially in colder climates. To maintain cleaning effectiveness and reduce aggressiveness, the technique has used synthetic surfactants to replace some or all of the soap. In particular, anionic surfactants have been used, because these tend to mimic more clearly the generation of foam that soap readily provides. Anionic surfactants, however, are still aggressive. One method of reducing the aggressiveness of anionic surfactants is to use other surfactants, such as non-ionic surfactants or other mild surfactants (for example amphoteric). The use of surfactants other than anionics, however, can introduce other problems. For example, non-ionic surfactants generally do not generate thick, creamy foam like anionics do; and both non-ionic and amphoteric surfactants for example can be sticky and introduce processing difficulties. For this reason, the technique is always looking for materials that are softer than anionic, and / or that can be used to replace at least some of the anionic surfactants, and still, that simultaneously do not seriously compromise foam generation or the efficiency of processing. In addition, even if the anionic surfactant is not replaced, the technique is always looking for materials that can replace inert materials and / or other fillers and produce an improved softness.

Unexpectedly, applicants have found that the use of relatively low concentrations of specific nonionic polymeric surfactants can be used to achieve these objectives. That is, even at a relatively low addition concentration of non-ionic polymeric surfactant (weight ratio of nonionic polymeric surfactant to anionic surfactant below 1: 1), it was found that the specified non-ionic polymeric surfactants significantly mitigate the irritation of the skin of anionic surfactants without sacrificing processability and foaming. In ratios by weight above 1: 1, the processability of the bar can be adversely affected; for example, the formulation can become highly viscous and sticky to cause extrusion difficulties. While not wishing to be bound by theory, it is believed that hydrophobically modified nonionic polymers may be interacting with the anionic surfactant to form polymer-surfactant complexes, thereby reducing the free anionic surfactant (known for its aggressiveness) of the bar. The use of nonionic polymeric hydrophobically modified polyethylene glycol (HMPEG) surfactants in bar compositions per se is not new.

U.S. Patent No. 3,312,627 to Hooker, for example, discloses bars substantially free of anionic detergents, comprising from 0 to 70% by weight of polyethylene glycol (PEG), or hydrophobically modified derivatives of these compounds as a base; and from 10 to 70% of a nonionic foam-forming component. To give these bars more "soap-like" characteristics, the reference contemplates the use of 10% - 80% lithium soap. It is clear that the use of lithium soap is unique to the invention (column 8, lines 20-23) and that the use of other soaps or anionic compounds (other than lithium fatty acid soap) is not contemplated. Thus, this reference clearly differs from the composition of the invention comprising from 10 to 70% of a surfactant system, of which at least 50% (although not more than 60% total of the total composition) is synthetic anionic surfactant. The. World Patent No. WO 9,317,088 given to Procter &; Gamble, for example, claims a soap-based bar, substantially free of synthetic anionic detergents, comprising 45-90% fatty acid soap, 1-8% C? 4-20E065-? Oo as a coactive agent, and 0.5-2% cationic polymer as an auxiliary of softness. The formulation had an improved control of the frothy cream. World Patent No. WO 9,304,161 given to Procter & Gamble claims soap-based bar formulations substantially free of synthetic anionic detergents, comprising 45-90% fatty acid soap, 0.5-10% C? -20EO20-250 (preferably C? -20E025-8o) as a coactive agent, and 0.5-10% acyl isethionate surfactant. The addition of small amounts of alkoxylated nonionic surfactants was to reduce the formation of frothy cream. Patent No. EP 311,343 given to G. Dawson and G. Ridley discloses a Beta phase toilet soap bar substantially free of synthetic anionic detergents, comprising 45-90% alkaline-soluble soap of C8 fatty acids. C24, 0.5-45% of a non-ionic alkoxylated surfactant having an HLB of 12-19.5, and 0.01 to 5% of a water-soluble polymer. The composition has an improved control of the frothy cream, with good smoothness, foaming, and transparency. U.S. Patent Nos. 4,247,425, 4,343,726, and 4,256,611 given to R. Egan disclose liquid cleansing formulations for the skin, containing anionic surfactant and polyalkylene glycols hydrophobically modified as softness enhancers. These patents demonstrated that only at relatively high addition concentrations of the hydrophobically modified polyalkylene glycols (ratio by weight of hydrophobically modified polyalkylene glycols / anionic surfactant above 1: 1 (preferably from 1: 1 to 4: 1)), the polyalkylene glycols Modified hydrophobically can significantly reduce the irritation of the anionic surfactant. WO-A-94/21778 describes a process for improving the manufacture of synthetic detergent bars, which uses a composition comprising 10-60% of a synthetic surfactant that is not soap, 10-60% of a water soluble material that it has a melting point in the region of 40-100 ° C, 5-50% of a water-insoluble material having a melting point in the region of 40-100 ° C, and up to 20% water. "WO -A-94/17172 describes a bar of soap in which the soap has been replaced to a certain degree by synthetic surfactants, and which uses a composition comprising 10-70% of a first anionic surfactant, 1-20% of a second surfactant, up to 35% of a free fatty acid, up to 25% of a soap, and 0.1-0.9% of a silicone material of viscosity 10,000-200,000 centistokes.In contrast, our in vivo and in vitro tests showed that at one level of much lower addition of hydrophobically modified polyalkylene glycols, (ratio by weight very below 1: 1), the alkylene oxide adduct of our selection can still significantly reduce the skin irritation potential of the anionic surfactant. This low level of addition is a critical aspect, because at a higher level of addition, the hydrophobically modified polyalkylene glycols can make sticky and viscous to the stick formulation, thereby causing problems in processing, such as difficulties during extrusion and the print.

BRIEF DESCRIPTION OF THE INVENTION The Applicants have now found that the use of relatively small amounts of nonionic polymeric surfactants of hydrophobically modified polyethylene glycol (HMPEG) defined in stick compositions comprising primarily synthetic anionic surfactant systems improves markedly and unexpectedly the softness of these bars.

More specifically, applicants' invention relates to stick compositions comprising: (a) 10% to 70% by weight of the total composition of a system of surfactants selected from the group consisting of anionic surfactants, non-ionic surfactants (different of hydrophobically modified polyethylene glycols), cationic surfactants, amphoteric surfactants and mixtures thereof; wherein the anionic surfactant comprises at least 50%, preferably at least 60% of the surfactant system, and wherein the anionic component additionally comprises no more than 60% by weight of the total composition; (b) 20% to 85% by weight, preferably 30 to 70% of the total composition of a rod structurant, selected from the group consisting of alkylene oxide compounds having a molecular weight from about 2000 to about from 25,000, preferably 3,000 to 10,000; free fatty acids of 8 to 22 carbon atoms, paraffin waxes; water soluble starches (for example maltodextrin); and alkanols of 8 to 20 carbon atoms; and (c) 2% to 35% by weight of the total composition of a hydrophobically modified polyethylene glycol (HMPEG); wherein the weight ratio of HMPEG to anionic surfactant is between 1: 1.5 to 1:10, preferably of 1: 3 to 1: 7. Above the range of this weight ratio, the prsability of the bar can be adversely affected, for example, the increased adhesiveness causes difficulties in extrusion and stamping; below the range of this ratio, the skin irritation of anionic surfactants can not be effectively mitigated. The composition may optionally comprise from 0% to 25%, preferably from 2% to 15% by weight of solvent, such as ethylene oxide or propylene oxide.

BRIEF DESCRIPTION OF THE FIGURES Figure la and Figure lb show the% of Zein dissolved by acyl isethionate / cocoa idopropyl betaine as a function of the concentration of nonionic polymeric surfactant. In contrast to PEG 8000, the POE (200) glyceryl stearate and POE (200) glyceryl tallowate significantly reduced the% of Zein dissolved in very low concentrations. Therefore, the irritation potential of a personal wash bar can be further reduced by including relatively low concentrations (i.e., a weight ratio of HMPEG: anionic component below 1: 1) or hydrophobically defined modified polyalkylene glycols in a complete composition in bar. Figure 2 shows that the HMPEGs of the invention significantly reduce skin irritation caused by sodium acyl isethionate at low addition levels (ie, a weight ratio of HMPEG: anionic component below 1: 1).

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to synthetic stick compositions, wherein most of the bar surfactant system comprises synthetic anionic surfactant; and hydrophobically-specific modified polyalkylene glycols which can be used in such bar compositions at relatively low concentrations or addition levels to significantly improve the softness of the stick without sacrificing prsability and foaming.

More specifically, the stick compositions comprise: (a) 10% to 70% by weight of the total composition of a surfactant system, wherein the surfactant system is selected from the group consisting of anionic surfactants, non-ionic surfactants (different of the EO-PO polymer), amphoteric surfactants, cationic surfactants and mixtures thereof, wherein the anionic surfactant comprises 50% or more, preferably 60% or more, of the surfactant system, and the anionic surfactant comprises not more than 60 % of the total composition; (b) 20% to 85% of the total composition of a structurant of the bar selected from the group consisting of polyalkylene glycols having a MW from about 2,000 to 25,000 (which may optionally include from 1% to 5% polyalkylene) higher molecular weight glycols, which have a MW from 50,000 to 500,000, especially around 100,000); fatty acids of 8 to 24 carbon atoms, preferably of 12 to 24 carbon atoms; paraffin waxes; water soluble starches (for example maltodextrin); and alkanoles of 8 to 20 carbon atoms (for example cetyl alcohol); and (c) 2% to 30% by weight of the total composition of a hydrophobically modified polyalkylene glycol nonionic polymeric surfactant; wherein the weight ratio of hydrophobically modified polyalkylene glycol surfactant to anionic surfactant is between 1: 1.5 to 1:10, preferably 1: 3 to 1: 1.7. Above the range of this weight ratio, the processability of the bar can be adversely affected, for example increased stickiness can cause difficulties in extrusion and stamping; below the range of this ratio, the skin irritation of anionic surfactants can not be effectively mitigated. Surfactant System The anionic detergent active agent which may be used may be aliphatic sulphonates, such as a primary alkane sulphonate (eg, 8 to 22 carbon atoms), primary alkane disulfonate (eg, 8 to 22 carbon atoms). carbon), alkene sulfonate of 8 to 22 carbon atoms, hydroxyalkane sulfonate of 8 to 22 carbon atoms or alkyl glycerol sulfonate ether (AGS); or aromatic sulfonates such as alkyl benzene sulfonate. The anionic surfactant may also be an alkyl sulfate (for example alkyl sulfate of 12 to 18 carbon atoms) or alkyl ether sulfate (including alkyl glycerol ether sulfates). Among the alkyl ether sulfates are those having the formula: RO (CH2CH20) nS03M wherein R is an alkyl to alkenyl having 8 to 18 carbon atoms, preferably 12 to 18 carbon atoms, n has an average value greater than 1.0, preferably greater than 3; and M is a solubilizing cation such as sodium, potassium, ammonium or substituted ammonium. Sodium ammonium lauryl ether sulfates are preferred. The anionic surfactant can also be alkyl sulfosuccinates (including mono- and dialkyl sulfosuccinates, for example from 6 to 22 carbon atoms); alkyl and acyl taurates, alkyl and acyl sarcosinates, sulfoacetates, phosphates and alkyl phosphonates of 8 to 22 carbon atoms, alkyl phosphate esters and alkylsyl alkyl phosphate esters, acyl lactates, succinates and monoalkyl maleates of 8 to 22 carbon atoms, sulfoacetates, alkyl glucosides and acyl isethionates. The sulfosuccinates may be monoalkyl sulfosuccinates having the formula: R402CCH2CH (S03M) C02M; Y amide sulfasauccinates-MEA of the formula: R4CONHCH2CH202CCH2CH (S03M) C02M wherein R4 is in the alkyl range of 8 to 22 carbon atoms, and M is a solubilizing cation. Sarcosinates are usually indicated by the formula: R'CON (CH3) CH2C02M, wherein R 'is in the alkyl range of 8 to 22 carbon atoms, and M is a solubilizing cation. Tauratos are generally identified by the formula: R2CONR3CH2CH2S03M wherein R2 is in the alkyl range of 8 to 18 carbon atoms, R3 is in the alkyl range of 1 to 4 carbon atoms, and M is a solubilizing cation. Particularly preferred are acyl acyl isethionates of 8 to 18 carbon atoms. These esters are prepared by the reaction between an 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 isethionates, when present, will generally be in the range of from about 10% to about 70% by weight of the total composition. Preferably, this component is present from about 30% to about 60%. The acyl isethionate can be an alkoxylated isethionate as described in Ilardi et al., US Patent No. 5,393,466, incorporated herein by reference. This compound has the general formula: wherein R is an alkyl group having 8 to 18 carbon atoms, m is an integer from 1 to 4, X and Y are hydrogen or an alkyl group having 1 to 4 carbon atoms, and M + is a cation monovalent such as, for example, sodium, potassium or ammonium. The anionic surfactant comprises 50% or more of the total surfactant system, but must comprise no more than 60% by weight of the total composition. Amphoteric detergents that can be used in this invention include at least one acid group. This may be a carboxylic or sulfonic 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. They will usually comply with a total structural formula: wherein R1 is alkyl or alkenyl of 7 to 18 carbon atoms; R2 and R3 are each independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 3 carbon atoms; m is 2 to 4; n is O to 1; X is alkylene of 1 to 3 carbon atoms, optionally substituted with hydroxyl, and Y is -C02- or -S03-. Suitable amphoteric detergents within the general formula above include simple betaines of the formula: and amido betaines of the formula: Where m is 2 or 3. In both formulas R1, R2, and R3 are as previously defined. R1 can be in particular a mixture of alkyl groups of 12 and 14 carbon atoms derived from coconut, so that at least half, preferably at least three quarters of the groups R1 are preferably methyl.

A further possibility is that the amphoteric detergent is a sulfobetaine of the formula. or where m is 2 or 3, or variants of these, in which - (CH2) 3S03 ~ is replaced by: OH -CH 2, CHCH, SO3 * in these formulas R1, R2, and R3 are as previously discussed. The nonionic component that can be used includes in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide, either alone or with propylene oxide. The specific nonionic detergent compounds are the condensed materials of alkyl [6 to 22 carbon atoms] phenols-ethylene oxide, the condensation products of aliphatic alcohols (8 to 18 carbon atoms) primary or secondary, linear or branched with ethylene oxide, and products made by the condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called non-ionic detergent compounds include large chain tertiary amine oxides, large chain tertiary phosphine oxides and dialkyl sulfoxides. The nonionic component can also be a sugar amide, such as a polysaccharide amide. Specifically, the surfactant may be one of the lactobionamides described in U.S. Patent No. 5,389,279 given to Au et al., Which is incorporated herein by reference, or may be one of the sugar amides described in Patent No. 5,009,814 given to Kelkenberg, incorporated herein by reference. Other surfactants that may be used are described in U.S. Patent No. 3,723,325 given to Parran Jr., which is also incorporated in the present application by reference.

The nonionic and cationic surfactants that may be used include any of those described in US Patent No. 3,761,418 given to Parran Jr. incorporated herein by reference in the present application. Those included are the aldobionamides described in U.S. Patent No. 5,389,279 given to Au et al. and the polyhydroxy fatty acid amides described in US Pat. No. 5,312,934 given to Letton, which are incorporated by reference in the present application. The surfactants generally comprise from 10 to 50% of the total composition, except as noted that the anionic component comprises 50% or more of the surfactant system, and not more than 40% of the total. A preferred surfactant system is one that comprises acyl isethionate and an amphoteric component, ie betaine, as a co-surfactant. Structuring The structuring agent of the invention can be a water-soluble or water-insoluble structure. Water-soluble structurants include polyalkylene oxides of moderately high molecular weight of suitable melting point (for example from 40 ° to 100 ° C, preferably from 50 ° to 90 ° C), and in particular polyethylene glycols or mixtures thereof . The polyethylene glycols (PEG's) that are used can have a molecular weight in the range of 2,000 to 25,000, preferably 3,000 to 10,000. However, in some embodiments of this invention it is preferred to include a very small amount of polyethylene glycol with a molecular weight in the range of 50,000 to 500,000, especially molecular weights of about 100,000. It has been found that such polyethylene glycols improve the wear rate of the bars. It is believed that this is because the large chains of the polymer remain entangled even though the composition of the bar becomes wet during use. If such high molecular weight polyethylene glycols (or any other water soluble high molecular weight polyalkylene oxide) are used, the amount is preferably from 1% to 5%, more preferably from 1% to 1.5% to 4% or 4.5 % by weight of the composition. These materials will generally be used in conjunction with a large amount of another water soluble structurant, such as the polyethylene glycol mentioned above of molecular weight 2,000 to 25,000, preferably 3,000 to 10,000.

Water soluble starches (for example maltodextrin) can also be included in concentrations of 1% to 15% by weight of the total composition. Water-insoluble structurants also have a melting point in the range of 40-100 ° C, more preferably at least 50 ° C, notably 50 ° C to 90 ° C. Suitable materials that are particularly considered are fatty acids , particularly those that have a carbon chain of 12 to 24 carbon atoms. Examples are lauric, myristic, palmitic, stearic, arachidic and behenic acids and mixtures thereof. The sources of these fatty acids are coconut, primarily distilled coconut, palm, palm kernel, babassu and sebaceous fatty acids, and partially or fully hydrogenated fatty acids, or distilled fatty acids. Other suitable water insoluble structurants include alkanols of 2 to 20 carbon atoms, particularly cetyl alcohol. These materials generally have a solubility in water of less than 5 g / liter at 20 ° C. Soaps, (for example sodium stearate), can also be used, in concentrations of about 1% to 15% by weight. The soaps can be added without mixing, or made in situ by adding a base, for example NaOH, to convert the free fatty acids. The relative proportions of the water-soluble structurants and the water-insoluble structurants govern the rate at which the rod wears during use. The presence of the water insoluble structurant tends to retard the dissolution of the bar when exposed to water during use, and hence retards the rate of wear. The structurant is used in the bar in an amount of 20% to 85%, preferably 30% to 70% by weight. Polyalkylene Hydrophobically Modified Glycols The hydrophobically modified polyalkylene glycols (HMPEG) of the present invention are generally commercially available nonionic polymeric surfactants having a broad molecular weight range, from about 3000 to 25000 (preferably from 4000 to 15000) and a temperature of melting from about 25 ° C to 85 ° C, preferably from 40 ° to 65 ° C. Below the defined molecular weight range, HMPEG can make sticky stick formulations, and thus cause processing problems, such like difficulties in the extrusion and the stamping. Above this range, HMPEG can make highly viscous stick formulations, and can cause mixing difficulties. In general, the polymers will be selected from alkylene nonionic polymers terminally chemically linked by hydrophobic portions. A detailed description of the hydrophobic portions (R) is presented in Table 1. These polymers are usually commercially available. To ensure solubility in water, we prefer that the portion of the ethylene oxide moiety per mole be between 60% by weight and 99% by weight (preferably 85% by weight to 97% by weight). In other words, the total content of the hydrophobic portion is between 2% by weight and 30% by weight (preferably 3% by weight to 15% by weight) in each mole of hydrophobically modified alkylene glycol. The hydrophobic portion (s) may be derived from linear or branched alkyls, acyls, and aryls, alkylaryls, and alkenyls having from 2 to 60 carbon atoms, preferably from 8 to 40 carbon atoms. The detailed description of the hydrophobic portion (s) is presented in Table 1.

Specifically, examples of various hydrophobically modified polyalkylene glycols are set forth in Table 1 below, wherein the Tm (° C) were obtained from the literature of the corresponding chemical suppliers, or were measured by the inventors using a calorimetric technique. differential sweep. Table 1. Representative hydrophobically modified PEGs (R = hydrophobic portions, such as alkyl, aryl, alkylaryl, alkene, acyl derivatives; and fatty and petroleum derivatives of alkylglycerol, glyceryl, sorbitol, lanolin oil, coconut oil, jojoba oil, castor oil, almond oil, peanut oil, wheat germ oil, rice bran oil, flaxseed oil, apricot kernel oil, walnut, palm kernel, pistachio nut, sesame seed, rapeseed oil, corn oil, peach kernel oil, poppy seed oil, pine oil, soybean oil, avocado oil, sunflower seed oil, hazelnut oil, olive oil, grape seed oil, safflower oil, seed oil Butyrospermum parkii, babassu oil, etc.

POE = polyoxyethylene or polyethylene glycol; m = Number of ethylene oxide monomer units; preferably m = m > 40; more preferably m > fifty) . Chemical Compounds Suppliers (Trademarks) Comments POE (m) -R Witco (Varonic LI-420) R = Glyceryl tallowate m = 200; solid white. Seppic (Simusol 220TM) R = glyceryl stearate; m = 200; white Amerchol (Glucam E-200) R = glycoside; m = 200; white solid, soluble in water; solid white. Calgene Chemical (600-S) Tm: 52-62 ° C; R = stearate; m = 150; Tm: 52-62 ° C. Calgene Chemical (600-L) R = laurate; m = 150. R-P0E (m) -R Stepan (KESSCO PEG 6000 R = stearate; distearate) m = 174; Ti: 54 'C, white solid.

As noted, the melting temperature of the compounds should be around 25 ° C-85 ° C, preferably 40 ° C to 65 ° C, the latter being more favorable for processing (for example, the flakes are formed more easily, and the pieces are more easily extruded). The bars of the invention may comprise from 0% to 25%, preferably from 2% to 15% by weight of an emollient such as ethylene glycol, propylene glycol and / or glycerin. Other Ingredients The stick compositions of this invention will usually contain water, but the amount of water is only a very small proportion of the stick. Larger amounts of water reduce the hardness of the bars. It is preferred that the amount of water is not over 15% by weight of the bars, preferably from 1% to about 10%, more preferably from 3% to 9%, more preferably from 3% to 8%. The bars of this invention may optionally include so-called benefit agents-materials included in relatively small proportions, which confer some additional benefit to the basic cleaning action of the bars. Examples of such agents are: skin conditioning agents, including emollients such as fatty alcohols and vegetable oils, essential oils, waxes, phospholipids, lanolin, antibacterial agents and disinfectants, opacifying agents, pearly-like agents, electrolytes , perfumes, sunscreen agents, fluorescent agents and coloring agents. Preferred skin conditioning agents comprise silicone oils, mineral oils and / or glycerol. The examples below are proposed to better illustrate the invention, but are not intended to be limiting in any way. All percentages, unless noted otherwise, are proposed to be percentages by weight.

EXAMPLES Methodology Assessment of Softness The zein dissolution test was used to preliminarily investigate the irritation potential of the formulations studied. In a 256 ml (8 ounce) container, 30 ml of an aqueous dispersion of a formulation was prepared. The dispersions were placed in a bath at 45 ° C until they were completely dissolved. When equilibrated to room temperature, 1.5 g of zein powder was added to each solution with rapid stirring for one hour. The solutions were then transferred to centrifuge tubes, and subjected to centrifugation for 30 minutes at approximately 3,000 rpms. The undissolved zein was isolated, rinsed and allowed to dry in a vacuum oven at 60 ° C at a constant weight. The percent of solubilized zein, which proportional to the irritation potential, was determined gravimetrically. The 3-Day Patch Test Protocol The patch test was used to evaluate the skin softness of aqueous dispersions containing 1% DEFI active agent (sodium cocoyl isethionate) and different concentrations of the structuring / coactive agents. Patches (Hilltop ™ Chambers, 25 mm in size) were applied to the outer arm of the panelists under bandage-type bandages (Scanpor ™ tape). After each designated contact period (24 hours for the first application of the patch, 18 hours for the second and third applications), the patches were removed, and the sites were classified visually in order of severity (erythema and dryness) by trained examiners under a consistent lighting.

Processing of Formulations Bar formulations were prepared in a 2-liter Patterson mixer with a sigma type paddle. The components were mixed together at ~95 ° C, and the water concentration was adjusted to approximately 8-10% by weight. The batch was covered to prevent moisture loss, and mixed for about 15 minutes. Then the cover was removed, and the mixture allowed to dry. The moisture content of the samples taken at different times during the drying step was determined by Karl Fisher titration with a turbo titrator. At the final moisture concentration (~5%), the formulation was poured onto a heated applicator roll, and flaked on a cooled roll. The scales of the cooled roller were extruded under vacuum in a Weber Seelander double refiner with a screw speed of ~ 20 rpm. The extruder nose cone was heated to "45-50 ° C. The cut pieces were stamped into bars using a Weber Seelander L4 hydraulic press with an appropriate pillow-shaped nylon nozzle, bars were also prepared by a molding process by melting First, the components were mixed together at 80-120 ° C in a 500 ml container, and the water concentration was adjusted to approximately 10-15% by weight.The batch was covered to prevent moisture loss, and mixed for about 15 minutes, then the cover was removed, and the mixture allowed to dry.The moisture content of the samples taken at different times during the drying step was determined by Karl Fisher titration with a turbo titrator. At the final moisture concentration (~ 5%), the mixture in the vessel (in the form of a free-flowing liquid) was poured into bar molds, and allowed to cool to room temperature for four hours. mix molded into the bar mold in a bar.

Example 1 The components listed in Table 2 below were melted together at 80 ° C-120 ° C to produce a material that consisted predominantly of a liquid phase. All quantities are given in percentage by weight. Upon cooling to 10 ° C - 50 ° C by a cooling roller, the formulations formed plastic-like solids, which were extruded using the extrusion equipment described above (ie, the formulation processing section) and compressed into bars using the individual bar press. Also identical bar formulations were formed using the hot melt molding process. These bars contain a major active agent of DEFI and an optional co-active agent of cocoamidopropyl betaine. These bars provided a rich, creamy and unctuous foam; it was found that the cutaneous sensation of the bars was smooth and not sticky.

TABLE 2 * DEFI: directly esterified fatty acid isethionate, which is a mixture containing about 74% by weight of fatty acid isethionate, 23% of stearic-palmitic acid and small amounts of other materials, manufactured by Lever Brothers Co. , U.S. ** PEG 8000: polyoxyethylene glycol with an average molecular weight of 8000; PEG 4000: polyoxyethylene glycol with an average molecular weight of 4000.

Example 2 The components listed in Table 3 below were preferably processed using a melt-casting approach described in the methodology section. All quantities are given in percentage by weight. These bars used sodium lauryl sarcosinate (Formulation E, G) and sodium lauryl ether sulfate (Formulation F) as the main anionic detergent with optional cocoamidopropyl betaine as a coactive agent. These bars provided a rich, creamy and unctuous foam and a soft skin sensation.

TABLE 3 Example 3 The irritation reduction potential of the hydrophobically modified polyalkylene glycols was investigated using Zein dissolution experiments. As indicated in Figures la and lb, the hydrophobically modified polyalkylene glycols, as a class, are significantly more effective than PEG in reducing the% of Zein dissolved by 1% to 2% aqueous suspension of DEFI (DEFI is a mixture of sodium acyl isethionate / fatty acid defined in T 2 of Example 1 ). The data in Figure la and lb also showed that at relatively low levels of hydrophobically modified polyalkylene glycol (the weight ratio of hydrophobically modified polyalkylene glycol to anionic surfactant is below 1: 1), the hydrophobically modified polyalkylene glycols reduced significantly the amount of zein dissolved by the DEFI.

EXAMPLE 4 The three-day skin patch tests showed that an HMPEG, namely POE (200) glyceryl stearate, significantly reduced skin irritation caused by sodium acyl isethionate, even at low addition concentrations. As shown in Figure 2, in a weight ratio of sodium acyl isethionate (SAI) / POE (200) glyceryl stearate of about 1: 0.74 (equivalent to 20% of POE (200) glyceryl stearate in the bar containing 27% sodium acyl isethionate), POE (200) glyceryl stearate reduced the skin irritation of a DEFI / betaine liquor significantly. In contrast, even in a weight ratio of SAI to PEG 8000 as low as 1: 1.67 (effectively 45% of PEG 8000 in a bar with 27% of SAI (formulation D, Table 2) the PEG 8000 did not make a measurable contribution to the softness of the aqueous liquor of SAI / CAP betaine.

Claims (12)

1. A bar composition, characterized in that it comprises: (a) 10% to 70% by weight of the total composition of a system of surfactants selected from the group consisting of anionic surfactants, non-ionic surfactants other than the point non-ionic polymer surfactant ( c) below, cationic surfactants, amphoteric surfactants and mixtures thereof, wherein the anionic surfactant comprises 50% or more of the surfactant system, and wherein the anionic surfactant comprises no more than 60% by weight of the total composition; (b) 20% to 85% by weight of the composition of a rod structurant, selected from the group of alkylene oxide components * having a molecular weight from about 2000 to about 25,000; free fatty acids of 8 to 22 carbon atoms, paraffin waxes; Water soluble starches; alkanols of 8 to 20 carbon atoms; and (c) 2% to 30% by weight of the total composition of a hydrophobically modified polyalkylene glycol polymer surfactant having the structure: R- (OCH 2 CH 2) mR or R- (OCH 2 CH 2) m wherein m is greater than 40, having a molecular weight in the range of 3,000-25,000 and a melting temperature in the range of 25-85 ° C, and wherein R is selected from linear or branched alkyls, acyls, aryls, alkylaryls, or alkenyls of 2 to 60 carbon atoms, or fat and petroleum derivatives, and wherein the weight ratio of the total hydrophobic modified polyalkylene nonionic polymer composition to anionic surfactant is between 1: 1.5 to 1:10.

2. A composition according to claim 1, characterized in that the surfactant system comprises any of (i) anionic, amphoteric or mixtures thereof; "or (ii) acyl isethionate and betaine.

3. A composition according to any of claim 1 or claim 2, characterized in that the structurant (b) comprises from 30% to 70% of the bar.

4. A composition according to any of the preceding claims, characterized in that the structurant (b) is an alkylene oxide component, and has a molecular weight of 3,000-10,000.

5. A composition according to any of the preceding claims, characterized in that the melting temperature of "c) is from 25 ° C to 85 ° C, optionally between 40 ° C to 65 ° C.

6. A composition according to any of the preceding claims, characterized in that the molecular weight of (c) is between 4,000 to 15,000.

7. A composition according to any one of the preceding claims * characterized in that the portion of the ethylene oxide moiety per mole of (c) is between 85% by weight to 97% by weight.

8. A composition according to any of claims 2-7, characterized in that the weight ratio of (c) to anionic surfactant is between 1: 3 and 1: 7.

9. A composition according to any of the preceding claims, characterized in that it additionally comprises an emollient.

10. A composition according to claim 9, characterized in that the polyol is selected from the group consisting of ethylene glycol, propylene glycol, glycerol and mixtures thereof.

11. A composition according to any of the preceding claims, characterized in that R is a hydrophobic portion of 8 to 40 carbon atoms.

12. A composition according to any of the preceding claims, characterized in that the R portions of each mole of the hydrophobically modified polyalkylene glycol polymer surfactant are between 3 and 15% by weight of the structure.