WO2013092309A2

WO2013092309A2 - Sulfate-free and peg-free body cleansers

Info

Publication number: WO2013092309A2
Application number: PCT/EP2012/075101
Authority: WO
Inventors: Wolfang FIEBER; Vera Tchakalova; Glenn Verhovnik; Patricia KNÖRR CARON
Original assignee: Firmenich Sa
Priority date: 2011-12-19
Filing date: 2012-12-11
Publication date: 2013-06-27
Also published as: WO2013092309A3; BR112014014976A2

Abstract

The invention relates to a perfumed aqueous viscous, sulfate-free and PEG-free, personal cleansing compositions, essentially formed of a surfactant system based on a specific combination of anionic and non-ionic natural substances, an electrolyte and water. The components are specifically selected and used in defined concentrations where high viscosities can be achieved without the addition of polymeric thickeners. Upon application, the body cleansing compositions such as shower gels, liquid hand soaps and shampoos, provide a surprising fragrance "blooming" effect.

Description

SULFATE-FREE AND PEG-FREE BODY CLEANSERS

Technical field

The present invention relates to the field of perfumed body cleansing compositions and more specifically to shampoos, shower gels and liquid hand soaps that are free of sulfate and PEG-containing surfactants.

Prior art

The large majority of known consumer products in personal care, such as shower gels, shampoos, or liquid hand soaps, are based on sulfate containing surfactants such as SLS (sodium lauryl sulfate) or SLES (sodium laureth sulfate). These surfactants are cheap raw materials, have good cleaning efficiency and foaming properties, and can be easily thickened by the addition of sodium chloride. SLES is a synthetic product and, compared to SLS, contains an additional oligo-polyethyleneglycol (PEG) moiety and is considered as a milder surfactant.

However, consumer interest and awareness has changed in the last few years and there is an increasing demand for safe, environment friendly, natural and/or sustainable products. SLS is regarded as being potentially irritant for sensitive skin. On the other hand, PEG containing products such as SLES originate from petrochemistry and may contain undesired contaminants, such that it may also be desirable to formulate body cleansing products free of sulfate and PEG based surfactants. In this context, most of the generally reported studies relate to the use of surface active agents derived from naturally occurring amino acids, such as glutamates, taurates or sarcosinates, and non-ionic surfactants such as alkyl(poly)glucosides or sucrose esters.

It is desirable to obtain viscous composition for cleansing composition. For shampoo, shower gel and liquid hand soaps formulations an elevated viscosity is necessary for the usage under application conditions. For sulfate containing surfactants such as SLS or SLES viscosity can be increased relatively easily by the addition of small amounts of salt, e.g. NaCl. However, this is not the case for anionic surfactant of the acetylated amino acid type. Even at very high salt concentrations aqueous solutions are still fluid and not usable for the targeted applications. On the other hand, non-ionic surfactants cannot be thickened at all by the addition of electrolytes. The use of electrolytes such as NaCl does therefore not provide compositions having an adequate viscosity for use as body care cleansers. Formulations involving the use of a thickener of gums, such as xanthan gum, are not always desirable since they have a structuring effect on the gel imparting elastic properties thereto which leads to the formation of thick lumps when drawing the formulation out of the bottle. The use of other polymeric thickeners for formulations containing natural surfactants is also not desirable since they often contain polyethyleneglycol (PEG) moieties originating from petrochemical sources. Therefore the usage of electrolytes and an adequate mixture of surfactants for the thickening of the formulations is preferable.

For instance, in WO 86/02943 monoglycosides are used as viscosity modifiers in detergents as mixtures with anionic surfactants from the group of sulfates, sulfonates or alkylcarboxylates.

In US 4,668,422 the formulation of a liquid hand soap is described containing APG, betaines and nonionic amino oxides or amides.

One document in particular reports a cosmetic composition devoid of sulfate or

PEG derivatives as surfactant. In WO02/056840 it is mentioned a manner to viscosify compositions by using a surfactant mixture of at least one anionic amino acid surfactant and one alkylpolyglycosides in a ratio of 1/49 to 1/1 and optionally, as additive, a perfume oil. Said document exemplify only N-acyl glutamate or aspartate as anionic amino acid surfactant. However, said prior art compositions if before addition of the perfume disclose an acceptable viscosity for cleansing composition, after addition of the perfume display a very significant drop in viscosity, which is obviously a drawback.

The aim of the present invention is to palliate drawbacks of the prior art disclosures, by providing cleansing compositions displaying superior viscosities even in the presence of a perfume oil, or which allows the use of a decreased amount of surfactant systems for obtaining a similar viscosity.

Description of the invention

The invention relates to a perfumed aqueous viscous cleansing composition which is free of sulfate-containing and PEG-containing surfactants and which comprises:

a. about 5% to 40% w/w of a surfactant system consisting of: (A) at least an anionic amino acid surfactant selected from the group consisting of salts of N-acyl sarcosinate, N-acyl glycinate, N-acyl alaninate, and any mixture thereof; and

(B) at least a non-ionic surfactant selected from the group consisting of alkylpolyglycosides (APG), or mixtures thereof; and

(C) between 0% and 4% w/w of other sulfate-free or PEG-containing free surfactants

wherein the w/w ratio (A)/(B) is comprised between above 1 and about 10; and the w/w ratio (C)/(B) is comprised between below 1 and 0;

about 0.1 to 10% w/w of an electrolyte;

about 0.1 to 5.0% w/w of a perfume oil;

water q.s. to 100% w/w

percentages being relative to the total weight of the composition. By the term "q.s." it is meant the expression "quantum satis" i.e. the amount required to complete to 100%.

By the term "viscous" it is meant here a composition that has viscosity which is from 0.1 to 50 Pa.s, at zero-shear. Zero-shear viscosity η was determined from flow curves (viscosity = f (shear rate) by increasing the shear rate from 1 to 100 s^"1. The plateau value of the viscosity at low shear rates was defined as the zero-shear viscosity.

According to more specific embodiments, the composition is characterized by a viscosity of 0.5 to 10 Pa.s.

The terms "consists of or "consisting of in relation to the surfactant system are used here to meant that the composition comprises a surfactant system which is strictly formed of a mixture of anionic and non-ionic surfactants, and of the optional surfactants under C),such as defined above and contains no other surfactants.

By the expression "sulfate-containing and PEG-containing surfactants free" it is meant that the invention composition is devoid of any surfactant which is a derivative of a sulfate or a PEG (polyethylene glycol), such as sodium lauryl ether sulfate.

By the expression "cleansing composition" it is meant a composition aimed to the washing/cleaning and in particular for a body-care application, such as but not limited to shower-gel, liquid hand wash/soap or shampoo. The surfactant system of any embodiment of the composition according to the invention consists of at least an anionic amino acid surfactant and at least a non-ionic surfactant as defined above.

According to any one of the invention embodiments, the total amount of the surfactant system can be comprised between about 10% and 25% w/w relative to the total weight of the composition.

According to any one of the invention embodiments, said anionic amino acid surfactant is present in a concentration of 2.5% to 25%, or even of 5% to 15%, by weight relative to the total weight of the composition.

According to any one of the invention embodiments, said non-ionic surfactant is present in a concentration of 2% to 25%, or even of 5% to 15%, by weight relative to the total weight of the composition.

According to any one of the invention embodiments, the w/w ratio (A)/(B) is comprised between about 1.1, or 1.5, and about 3.

According to the invention, the anionic surfactant component A is an N-acyl derivative of a sarcosinate, glycinate, or alaninate, or a mixture of these amino acid derivatives.

According to any one of the invention embodiments, in said anionic surfactant the acyl group is a Cs-22 group. In particular such acyl group can be the one corresponding to natural fatty acids.

According to any one of the invention embodiments, the anionic surfactant is an alkaline salt, such as sodium or potassium salt, or an ammonium salt.

The surfactants which are useful for the present invention can be of synthetic origin or of natural origin, e.g. materials composed in whole or in significant part of biological products or renewable agricultural materials, including plant, animal, and marine materials. Natural amino acid surfactants for the compositions of the invention are the reaction products of naturally occurring amino acids with long chain fatty acids, obtained by acetylation of the oc-amino functional group of the former.

Amongst the commercially available amino acid surfactants, the products sold by Zschimmer & Schwarz Italiana, Italy, under the commercial tradename Protelan^®, or those obtainable from Ajinomoto, Japan, under the commercial tradename Amilite^®, are particularly useful in the context of the invention. According to any one of the invention embodiments, said anionic surfactant or mixture of surfactants is comprised between about 5% and 15% relative to the total weight of the composition.

The non-ionic surfactants present in any one compositions of the invention are selected amongst the group formed by alkyl polyglycosides (APGs) and their mixtures. Amongst the commercially available APGs, the products sold by BASF GmbH, Ludwigshafen, Germany, under the commercial tradename Plantacare^®, are particularly useful in the context of the invention.

Alkyl polyglycosides are sugar-based surfactants, composed of carbohydrates derived from starch and of fatty alcohols from palm kernel or coconut oil.

According to any one of the invention embodiments, said non-ionic surfactant is selected from the group of alkylpolyglycosides with the common formula RO(G)_x, where R is a linear or branched chain alkyl group carrying between 8 and 22 carbon atoms, G is the residue of a reducing saccharide consisting of 5 or 6 carbon atoms, preferably glucose or maltose, and x expressing the degree of oligomerization is between 1 and 5, preferably between 1.1 and 1.5.

Table 1 contains a more preferred list of suitable surfactants for use in the compositions of the invention, as well as possible suppliers thereof and their respective product commercial designations.

TABLE 1 - Preferred surfactants

According to any one of the invention embodiments, it is advantageous that the hydrophobic tails of surfactant A and B carry about the same number of carbon atoms, i.e. N-acyl group of the anionic surfactant and the alkyl group of the non-ionic surfactant have the same or about the same number of carbons, and in particular when said number of carbon is comprised between 12 to 14. Indeed in such a case the compositions of the invention present highly preferred viscosity and other properties. Thus, the mixtures of the surfactant mentioned in the above Table 1 are preferred surfactant systems of the invention, as such surfactant combinations provide well- appreciated mild, rich skin feel, nurturing effect on application on the skin or hair.

As metioned above the surfactant system may comprise as optional component additional sulfate-free or PEG-containing free surfactants, which can be selected amongst anionic, amphoteric or non ionic surfactants.

According to a particular embodiment of the invention, said optional surfactants are incorporated in amounts varying between 0% and 2% w/w relative to the total weight of the composition.

According to a particular embodiment of the invention, the w/w ratio (C)/(B) is comprised between 0.5 and 0.

Non-limiting examples of such optional surfactant under C) are:

- anionic: alpha olefin sulfonates, alkyl sulfonates, alkyl aryl sulfonates, methylester sulfonates, acyl alkyl taurates, alkyl sulfosuccinates, acyl isethionates, alkyl phosphates, fatty acids;

- amphoteric: betaines, amine oxides; acyl amphoacetates and

- non ionic: sucrose esters, sorbitane esters, alkanol amides.

All of said cited surfactants are well known products.

By the term "electrolyte" we mean here ionic salt totally soluble in the composition at the concentrations used.

According to any one of the invention embodiments, the electrolyte of any composition according to the invention can be selected from the group of alkali, and ammonium salts. In particular such electrolyte can be an alkali salt. As non limiting examples, one may cite electrolyte such as NaCl or KC1.

According to any one of the invention embodiments, the electrolyte is present in the composition in a concentration of about 0.2 to 3% weight relative to the weight of the composition.

The cleansing composition of the invention comprises a perfume. Such perfume is fully solubilised in the composition by the surfactant system, i.e. it is not observed a phase separation between the water and the perfume oil phase. According to any one of the invention embodiments, the perfume oil is present in the composition in a concentration of about 0.2% to 2% weight relative to the weight of the composition.

Generally speaking, by "perfume oil" we mean here a perfuming ingredient or mixture of ingredients, and optionally one or more perfumery solvents or perfumery adjuvants commonly used in the perfume industry. By "perfuming compound" it is meant here a compound, which is of current use in the perfume industry, i.e. a compound which is used as ingredient in perfuming preparations or compositions in order to impart, modulate or modify the odor of the composition, article or product into which it is incorporated. In other words, such a compound, to be considered as being a perfuming one, must be recognized by a person skilled in the art as being able to impart or modify in a positive or pleasant way the odor of a composition, and not just as having an odor.

The nature and type of the perfuming compounds that can be used according to the invention do not warrant a more detailed description here, which in any case would not be exhaustive, the skilled person being able to select them on the basis of its general knowledge and according to intended use or application and the desired perfuming effect. In general terms, such perfume ingredients belong to chemical classes as varied as alcohols, aldehydes, ketones, esters, ethers, acetates, nitriles, terpene hydrocarbons, nitrogenous or sulphurous heterocyclic compounds and essential oils of natural or synthetic origin. Many of these co-ingredients are in any case listed in reference texts such as the book by S. Arctander, Perfume and Flavor Chemicals, 1969, Montclair, New Jersey, USA, or its more recent versions, or in other works of a similar nature, as well as in the abundant patent literature in the field of perfumery.

By "perfumery solvents" we mean here a solvent commonly used in perfumery. A detailed description of the nature and type of solvents commonly used in perfumery cannot be exhaustive. However, one can cite as non-limiting examples solvents such as dipropyleneglycol, diethyl phthalate, isopropyl myristate, benzyl benzoate, 2-(2- ethoxyethoxy)-l-ethanol or ethyl citrate, which are the most commonly used.

By "perfumery adjuvant" we mean here an ingredient capable of imparting an additional added benefit such as a color, a particular light resistance, chemical stability, etc. A detailed description of the nature and type of adjuvant commonly used in perfuming bases cannot be exhaustive, but it has to be mentioned that said ingredients are well known to a person skilled in the art.

According to a particular embodiment of the invention, said fragrance oil has a calculated logP comprised between about 1 and about 7, most preferably between 1 and 4.

For the sake of clarity, by "/ogPm x" it is intended the calculated logP of the mixture of perfume ingredients, which is obtained by the formula: logPmix =

wherein x; is the molar fraction and logPi is the calculated logP of the ¾ ingredient in the mixture of n perfumery ingredients.

Said "calculated /ogP" is the calculated logP for each single perfuming ingredient which can be obtained according to the program EPI suite (4.0); EPA (US Environmental Protection Agency) and Syracuse Research Corporation (SRC), 2000.

The invention's cleansing composition may further comprise additional optional ingredients which may bring specific benefits for the intended use but are not required to solubilise the perfume (e.g. optional benefit ingredient). Such optional ingredients may include colorants, pearlescent agents, emollients, hydrating agents, opacifiers, conditioning agents, preservatives and pH adjusters. The nature of the latter does not require a more detailed description here, as the skilled person is able to select according to general knowledge in the art of formulating body care gel compositions such as shampoos, shower gels and liquid hand soaps, and the vast literature there-related, appropriate such optional ingredients for application purposes.

According to any one of the invention embodiments, said optional benefit ingredient can be present in an amount comprised between 0% and 25%, or even between 0% and 10%, relative to the total weight of the composition.

According to any one of the invention embodiments, said cleansing compositions of the invention may have a pH comprised between 4 and 11.

Any one of the gel compositions according to the invention, which are personal care compositions, can be formulated in the form of a shower gel, a liquid soap, particularly for hand care, or a shampoo for hair care. Such formulation is carried out according to generally known processing methods. The concentrated products and the shower gel, liquid soap and shampoo products thus obtained are also embodiments of the invention. These shower gels, liquid soaps and shampoos present a creamy, rich texture with a pleasant and nurturing effect on skin during application, much different from, and far superior to, the effect provided by classical shower gel or liquid hand soap products.

Moreover, they can be entirely or predominantly composed of natural origin ingredients and environment friendly. Additionally, it has been unexpectedly found that surfactant formulations according to the present invention display increased release properties of added perfume oils upon dilution compared to a classical formulation containing SLES, which is a desired effect by the consumer during the application of the product. This has been confirmed by a sensory panel comprising 30 experienced persons. The fragrance mix was perceived significantly stronger upon dilution when applied in the surfactant base according to the preferred embodiments of the present invention, than in the classical shower gel base containing SLES.

The invention will now be described in further detail by way of the following examples, wherein the abbreviations have the usual meaning in the art. The temperatures are indicated in degrees centigrade (°C) and the other parameters in the respective current units. All viscosities η are zero-shear viscosities and are in Pa.s. All amounts are in w/w percentage relative to the total mass of the composition. Water amount indicated as "q.s." are intended to be "the amount required to complete to 100%".

Description of the Drawings:

Figure 1: Dynamic Headspace Analysis of Table 12 Shower Gels.

Dynamic headspace curve of fragrance evaporation at 37 °C from two different surfactant compositions: Invention shower gel (continuous line) and Comparative shower gel (dashed line). The dilution step with water (1:10) is at 45 min. The perfume used in the bases is a model mix containing 11 perfumery raw materials that cover a wide range of logP values (2.0 to 5.4) and of volatilities (12-35000 g/L air), respectively. The values indicated in the figure are averages of the gas phase concentrations in GC/MS (expressed in counts) over these 11 perfumery raw materials present in the sample. Examples

Formulae of the perfumes used in the Examples TABLE 2 - Composition of Fragrance 1

TABLE 3 - Composition of Fragrance 2

Ingredient logP Parts by weight

Hedione^® 2.92 20

Exaltolide^® 6.15 10

Ambrox^®8) 4.76 2

Neobutenone^®y) 4.45 0.1

Helvetolide^® 4.45 4

Dihydromyrcenol 3.21 20

Coranol^{IM 1U)} 3.98 10 IsoE^® super 4.71 26

Dipropylene glycol -0.67 7.9

Total mass 100

logPmix 3.74

TABLE 4 - Composition of Fragrance 3

Methyl dihydrojasmonate; origin: Firmenich SA, Geneva, Switzerland

pentadecenolide; origin: Firmenich SA, Geneva, Switzerland

(lS, R)-2-[l-(3',3'-dimethyl-l'-cyclohexyl)ethoxy]-2-methylpropyl propanoate; origin: Firmenich SA, Geneva, Switzerland

3- Methyl-5-cyclopentadecen-l-one; origin: Firmenich SA, Geneva, Switzerland tetrahydro-2-isobutyl-4-methyl-4(2H)-pyranol; origin: Firmenich SA, Geneva, Switzerland

1 - (octahydro-2 ,3,8,8 -tetramethyl-2-naphtalenyl) - 1 -ethanone ; origin : International Flavors & Fragrances, USA

pentadecanolide; origin: Firmenich SA, Geneva, Switzerland

(-)-(8R)-8,12-epoxy-13, 14,15, 16-tetranorlabdane; origin: Firmenich SA, Geneva, Switzerland

9) l-(5,5-dimethyl-l-cyclohexen-l-yl)-4-penten-l-one; origin: Firmenich SA, Geneva, Switzerland

4- cyclohexyl-2-methyl-2-butanol; origin: Firmenich SA, Geneva, Switzerland Example 1

Body Cleansing Compositions 1 to 24

Different formulations containing surfactant actives, salt, and fragrances were prepared. Typically, the surfactants were added subsequently to the water under stirring, and the pH was adjusted with 50% citric acid. Then NaCl was added under gentle stirring. Finally, the perfume was added to the mixture. Three fragrances were used that have different logP values (1.9, 3.7, 5.7), and the viscosities were compared to the viscosity of the formulation in the absence of fragrances (neat). Zero-shear viscosity η was determined for all formulations on a Bohlin C-VOR 150 rheometer at 25°C. A cone and plate geometry was used with a diameter of 4 cm and a cone angle of 2°. Flow curves were obtained by increasing the shear rate from 1 to 100 s^"1. The plateau value of the viscosity at low shear rates was defined as the zero-shear viscosity. TABLE 5 - Measured viscosity of the formulations according to the invention

Group Ref. 1 2 3 4

Ingredients Amounts w/w

Amilite^® ACS- 12 (A) 11 11 11 11

Plantacare^® 1200 UP ⁴ (B) 10 10 10 10

Total surfactant active 21 21 21 21

Ratio (A)/(B) 1.10 1.10 1.10 1.10

NaCl 1.5 1.5 1.5 1.5

Fragrance 0.0 1.0 1.0 1.0

Water (pH adjusted to 5.7) q.s. q.s. q.s. q.s.

η (neat) 3.04

η (Fragrance 1) 2.01

η (Fragrance 2) 1.46

η (Fragrance 3) 1.17

Ratio η (fragrance)^ (neat) 0.66 0.48 0.39 The present invention perfumed compositions showed viscosities which were comprised between about 40% and 65% of the reference without perfume.

TABLE 6 - Measured viscosity of the formulations according to prior art WO 02/056840.

The prior art perfumed compositions showed viscosities which were comprised between about 5% and 10% of the reference without perfume at best.

TABLE 7 - Measured viscosity of the formulations obtained with surfactants used in the present invention but with a ratio (A)/(B) according to prior art WO 02/056840

Group Ref. 9 10 11 12

Ingredients Amounts w/w

Amilite^® ACS-12 (A) 2 2 2 2

Plantacare^® 1200 UP ⁴ (B) 18 18 18 18

Total surfactant active 20 20 20 20

Ratio (A)/(B) 0.11 0.11 0.11 0.11 NaCl 0.2 0.2 0.2 0.2

Fragrance 0.0 1.0 1.0 1.0

Water (pH adjusted to 5.3) q.s. q.s. q.s. q.s.

η (neat) 8.37

η (Fragrance 1) 1.03

η (Fragrance 2) 0.42

η (Fragrance 3) Phase

separation

Ratio η (fragrance)^ (neat) 0.12 0.05

The out of the scope perfumed compositions showed viscosities which were comprised between about 5% and 15% of the reference without perfume at best. TABLE 8 - Measured viscosity of the formulations obtained with surfactants used in the present invention but with a lower ratio (A)/(B).

Ref. 13 14 15 16

Ingredients Amounts w/w

Amilite^® Α08-12 5 5 5 5

Plantacare^® 1200 UP ⁴⁾ 15 15 15 15

Total active 20 20 20 20

Ratio (A)/(B) 0.33 0.33 0.33 0.33

NaCl 1.0 1.0 1.0 1.0

Fragrance 0.0 1.0 1.0 1.0

Water (pH adjusted to 5.0) q.s. q.s. q.s. q.s.

η (neat) 8.44

η (Fragrance 1) 2.24

η (Fragrance 2) 0.81

η (Fragrance 3) 0.62

Ratio r|(fragrance)/r|(neat) 0.27 0.10 0.07 The out of the scope perfumed compositions showed viscosities which were comprised between about 5% and 25% of the reference without perfume.

TABLE 9 - Measured viscosity of other formulations according to the invention.

All fragrances led to a viscosity decrease compared to the neat formulations. Nevertheless, the extent of the decrease depends strongly on the ratio of anionic amino acid surfactant (A) and non-ionic sugar based surfactant (B). The decrease is significantly higher for ratios (A)/(B) < 1 than for ratios (A)/(B) > 1. For example, the viscosity decrease for the example presented in prior art WO 02/056840 is 90% and 95% for fragrances 1 and 2, respectively (examples 6 and 7), with a ratio (A)/(B) of 0.11. No stable formulation could be obtained with fragrance 3 due to phase separation. The formulation according to WO 02/056840 contains the amino acid surfactant sodium lauroyl glutamate. Replacing this one by an amino acid covered in the present invention, sodium cocoyl alaninate, and keeping a ratio of 0.11 about the same results could be observed (examples 10, 11, 12). On the other hand, with ratios of (A)/(B) > 1 (examples 2-4; 18-20, 22, 24) the viscosity reduction is significantly reduced. Examples 2-4 show a reduction of only 34% and 52% for fragrances 1 and 2, respectively.

This is an important property for formulation. Viscosity reduction through the addition of perfume has to be as low as possible in order to keep the viscoelastic properties of the cleansing base without having to reformulate it in the presence of perfume.

1) Sodium cocoyl alaninate, from Ajinomoto, Japan. Concentration of actives 30%.

2) Sodium cocoyl glycinate, from Ajinomoto, Japan. Concentration of actives 100%. 3) Sodium lauroyl glutamate, from Zschimmer & Schwarz Italiana, Italy. Dry matter 36 - 40%, NaCl content 3.0 - 4.5%.

4)

C12-16 glucoside, from BASF GmbH, Ludwigshafen, Germany. Concentration of actives 50-53%. Example 2

In the following we wanted to illustrate the advantage of formulations according to the patent. The surfactant active concentration of comparative formulations according to prior art using sodium lauroyl glutamate in combination with C₁₂-C₁₆ glucosides, at ratios (A)/(B) of 0.11 in the presence of fragrance 1, was increased in order to match the viscosity obtained with formulations of the invention. The surfactant active concentration had to be increased by 50% to achieve similar viscosities, as shown in Table 10 hereinbelow. TABLE 10 - Measured viscosity of the formulations according to the invention (2) and of the prior art (6, 24 & 25).

Group 2 6 24 25

Ingredients Amounts w/w

Amilite^® ACS- 12 (A) 11

Protelan^® AGL 95 ³⁾ (A) 2 2.5 3

Plantacare^® 1200 UP ⁴ (B) 10 18 22.5 27

Total active 21 20 25 30 Ratio (A)/(B) 1.1 0.11 0.11 0.11

NaCl 1.5 4 4 4

Fragance 1 1 1 1 1

Water (pH adjusted to q.s. q.s. q.s. q.s. value in brakets) (5.7) (5.9) (5.9) (5.9) η (Fragrance 1) 2.01 0.89 1.26 2.17

Example 3

Preparation of a Perfumed Shower Gel

A shower gel formulation according to the invention was prepared with the following base ingredients:

TABLE 11 - Composition of shower gel formulation

' Sodium cocoyl alaninate, from Ajinomoto, Japan. Concentration of actives 30%.

²⁾ C₁₂-16 glucoside, from BASF GmbH, Ludwigshafen, Germany. Concentration of actives 50-53%.

The base product was prepared by dissolving the preservative in water. Subsequently, C₁₂-16 glycoside, Na cocoyl alaninate and the 50% aqueous solution of citric acid as pH adjuster were added successively. The solution was heated at 40°C for 30 minutes. Finally, the NaCl was slowly added under gentle agitation in order to avoid formation of air bubbles. The product obtained presented a total surfactant content of 21% w/w, a pH of 5.7, and a zero-shear viscosity of 3.2 Pa.s. A perfumed shower gel was then prepared with the above base product by addition thereto of Fragrance 1, in a relative proportion of base product to perfume of 99:1. The perfumed shower gel thus obtained presented a zero-shear viscosity of 2.1 Pa.s. Example 4

Perfume release from a Shower Gel according to the invention

The release of perfume from a neat product (undiluted) and upon body application thereof under normal use conditions (i.e. during showering) of a personal cleansing composition according to the invention (Invention Shower Gel) was compared with the perfume release from a reference comparative formulation (Comparative Shower Gel) based on surfactant mixtures known from the prior art and formed of classical sulfate and PEG- containing surfactants. The concentration of surfactant actives was kept substantially the same in both products and the amount of NaCl adjusted so as to obtain two products with comparable viscosity. The perfume used is a mixture of 11 perfumery raw materials with logP values that range from 2.0 to 5.4 and volatilities between 12 and 35 '000 g/L air. The composition of the two shower gels is summarized in Table 12.

TABLE 12 - Composition of invention and comparative shower gels

Invention Shower Gel

Ingredients Amounts w/w

Amilite^® GCS-11 3.4

Plantacare^® 1200 UP ²⁾ 5.8

Protelan^® LS 9011 ^JJ 2.8

Citric acid 50% in water 0.35

NaCl 1

Perfume 0.5

Water q.s.

η (according to invention) 0.55 Comparative Shower Gel

Ingredients Amounts w/w

Texapon NSO IS ⁴ 9

Tego Betain F50 ⁵ 3

NaCl 0.75

Perfume 0.5

Water q.s.

η (not according to invention) 0.37

Sodium cocoyl glycinate, from Ajinomoto, Japan. Concentration of actives 100%. 2⁾ CI 2- 16 glucoside, from BASF GmbH, Ludwigshafen, Germany. Concentration of actives 50-53%.

3⁾ Sodium lauroyl sarcosinate, from Zschimmer & Schwarz Italiana, Italy. Dry matter 29%, NaCl content 0.5%.

⁴⁾ Sodium laurylethersulfate, from BASF GmbH, Ludwigshafen, Germany.

Concentration of actives 26.5 - 27.5%.

⁵⁾ Cocamidopropyl betain, from Evonik Goldschmidt GmbH, Essen, Germany.

Concentration of actives 38%.

Dynamic headspace analysis method

The evaporation of raw materials from the surfactant phases was measured by dynamic headspace technology. The method consists in the adsorption of components from the gas phase surrounding the sample (neat) onto a solid, porous material, a synthetic polymer Tenax^® (poly-diphenyl phenylene oxide). A constant flow rate of air through the cell and through the Tenax^® cartridge allows the adsorption (air sampling pump Gilian 113 DC, air flow 100 mL per minute).

In both cases, 2 g of the formulations described in Table 12 were placed into a thermostated vessel at 37°C. Samples were equilibrated for 15 minutes. At 45 minutes from the start of the test, 20 g of water at 37°C were added to the cell (dilution 1:10) and the solution was stirred with a magnetic stirrer. Sampling was carried out during 60 seconds at specific time points before and after the addition of water (at 15, 30, 43, 44, 45, 46, 47, 48, 49, 55, 70 minutes). After the samplings were made, cartridges containing the adsorbent were introduced into the automatic loader of the desorption system (Thermal Desorber UNITY with Auto- Sampler ULTRA TD, Markes Instruments). The headspace was thermally separated from the adsorbent and directed into a GC/MS (Column DB-lms, length 30 m x I.D 25 mm x film 0.25 μιη). The concentration in the gas phase (head space) in the measurement cell is proportional to the peak area obtained with GC/MS.

Table 13 below summarizes relative headspace concentration for the above Comparative shower gel and the above Invention shower gel, respectively. The values are normalized to 100 for the Comparative shower gel: neat (averaged over all perfumery raw materials at time points between 15 and 44 minutes) and dilution (averaged over all perfumery raw materials at time points between 46 and 49 minutes).

TABLE 13 - Results from dynamic headspace measurements.

Arbitrary units

As the results above show, whereas in "neat", i.e. undiluted, conditions, the fragrance release is comparable for the two products, a significant increase in headspace concentration was observed for the perfume contained in the shower gel according to the invention, relative to that released from the comparative shower gel.

This is also clearly seen in Figure 1 wherein the so-called "blooming" effect caused by the dilution of the shower gel base at approximately 45 min is clearly stronger from the invention's shower gel. This more intense blooming effect upon dilution with water is an unexpected and very desirable characteristic of the shower gels of the invention, as it increases the pleasant perception of the perfume by the user when showering. Sensory Test

The analytical results described here-above were also confirmed in a blind sensory test carried out with a panel of evaluators.

The olf active performance of the two products of Table 12, the invention shower gel and the comparative shower gel, were compared following the process described here -below.

Sample preparation

1) Neat: 40 g of each shower gel was put into a 50 ml brown PET bottle

2) Diluted: instant dilution was carried out in an open beaker by pouring 45 ml of tap water at 38°C onto 5 g of each shower gel, and the aqueous mixture was stirred for 10 seconds.

Sensory evaluation

The two neat, respectively diluted samples of the two shower gels were presented in a blind, balanced, randomised, and sequential monadic manner, to a panel of 30 untrained but experienced panelists, male and female. The panel individuals were asked to evaluate the fragrance intensity of each sample and rate it on an unlabelled continuous 0-10 line scale, wherein 0 = not perceptible odor and 10 = very strong odor.

The data obtained from the panel's ratings were analysed using analysis of variance with Duncan's post-hoc analysis (a = 0.05) and represented on a bar chart with 95% error bars.

The results observed were statistically significant and showed that there was no significant difference between the fragrance intensity perceived by the panel from the two neat samples. Upon dilution however, the perfume intensity perceived by the panel from the invention's shower gel was significantly stronger than that of the perfume released from the diluted comparative shower gel.

Claims

1. A perfumed aqueous viscous cleansing composition which is free of sulfate-containing and PEG-containing surfactants and which comprises:

a. about 5% to 40% w/w of a surfactant system consisting of:

(A) at least an anionic amino acid surfactant selected from the group consisting of salts of N-acyl sarcosinate, N-acyl glycinate, N-acyl alaninate, and any mixture thereof; and

(B) at least a non-ionic surfactant selected from the group consisting of alkylpolyglycosides, or mixtures thereof; and

b. about 0.1 to 10% w/w of an electrolyte;

c. about 0.1 to 5.0% w/w of a perfume oil;

d. water q.s. to 100% w/w

all percentages being relative to the total weight of the composition.

2. A cleansing composition according to claim 1, wherein the total concentration of surfactant system is of 10 to 25% by weight, relative to the weight of composition.

3. A cleansing composition according to claim 1 or 2, characterized in that the composition has a zero-shear viscosity of 0.1 to 50 Pa.s.

4. A cleansing composition according to any one of claims 1 to 3, characterized by a w/w ratio (A)/(B) comprised between about 1.1 and about 3.

5. A cleansing composition according to any one of the claims 1 to 4, characterized in that the component B of the surfactant system is selected from the group of alkylpolyglycosides with the common formula RO(G)_x, where R is a linear or branched chain alkyl group carrying between 8 and 22 carbon atoms, G is the residue of a reducing saccharide consisting of 5 or 6 carbon atoms, preferably glucose, and x expressing the degree of oligomerization is between 1 and 5, preferably between 1.1 and 1.5.

6. A cleansing composition according to any one of the claims 1 to 5, characterized in that the electrolyte is an alkali or ammonium salt.

7. A cleansing composition according to any one of the claims 1 to 6, characterized in that the fragrance oil has a calculated logP comprised between about 1 and about 4.

8. A cleansing composition according to any one of the claims 1 to 7, characterized in that the pH of the composition is comprised between 4 and 11.

9. A cleansing composition according to any one of the claims 1 to 8, characterized in that it is in the form of a shower gel, a liquid soap, particularly for hand care, or a shampoo for hair care.

10. A cleansing composition according to any one of the claims 1 to 8, characterized in that group C) of the surfactant system is present at 0%.