MXPA06001902A - Liquid compositions which thicken on dilution and methods for producing the same. - Google Patents

Abstract

The invention relates to a process for making single phase dilution thickening compositions comprising electrolyte. By adding defined associative thickener to said compositions applicants have found one can lower level of salt/electrolyte required to obtain dilution thickening effect. The invention also relates to single phase dilution thickening compositions both electrolyte and associative thickener. The two act synergistically to lower level of salt required for thickening to provide high viscosity retention and to provide a cohesitivity perceived by consumers as improved retention.

Description

LIQUID COMPOSITIONS THAT ARE EXPECTED IN DILUTION AND METHODS TO PRODUCE THEMSELVES The present invention relates to liquid cleaning compositions which have a viscosity which allows them to be easily emptied from a bottle or container, but whose viscosity increases during dilution / rinsing. The invention also relates to a process for lowering the level of salt required to produce a thickener effect of dilution using associative thickeners. Compositions comprising such thickeners are characterized by a cohesive "film" that is formed on treated skin which, in turn, prevents rinsing, as measured by a rinse retention test, and allows for enhanced ease of spreading. The use of salts to thicken surfactant systems and intensify viscosity is not new (see Canadian Patent No. 2,211,313). Normally, a so-called peak viscosity is reached when the salt is first added, and further addition of salt leads to viscosity reduction (this is known as over-salting). When the composition is diluted, the "sticky" composition then increases in viscosity once more in a process referred to as "dilution thickening". The thickened dilution compositions will normally form a skin film which lacks cohesion. As such, the film will dissolve and wash quickly. As such, thickener dilution compositions are generally perceived as easily rinsing and difficult to spread. Unexpectedly, applicants have found that when, in addition to the level of salt required to form "sticky" compositions, an associative thickener (e.g., hydrophobically modified PEG, such as PEG-200 glyceryl seboate, such as Rewoderm® LIS75 or PEG-7 glyceryl cocoate is also used, the film on the skin is much more cohesive, thus leading to reduced rinsing and greater spreading on the cleaned surface, which in turn allows the consumer to use less product and offers sensory benefit , both with or without the use of additional applicator / implement during use.In addition, applicants have found that the use of associative thickener decreases the amount of salt necessary to induce dilution thickening WO 94/16680 for Unilever describes thickened aqueous dilution, concentrated liquids comprising 20% to 60% of different surfactant of soap or primary alcohol sulfate. They form a lamellar phase of low viscosity in the undiluted product and, when diluted, form a more viscous hexagonal or bar phase. The compositions of the present invention do not require such high levels of surfactant (ie, in reference '680 it is the combination of surfactant and electrolyte, which initially form the lamellar phase of low viscosity) due to, it is believed, that thickening of dilution occurs by a different mechanism, that is, the combination of electrolyte / salt and hydrophobically modified associative thickener that forms a "film", which will thicken the dilution more than the lamellar phase of electrolyte and surfactant which will thicken the dilution. Furthermore, there appears to be no disclosure of the hydrophobically modified associative thickeners of the invention, or of the effect of such thickeners to lower the level of salt required for dilution thickening, namely enhanced rinse retention and ease of spreadability based on the Synergistic combination of the associative thickener and the electrolyte. The Canadian patent no. 2,211,313 also describes compositions which have been protruded and increase in viscosity upon dilution. Although there is a broad list of thickeners described (page 9, third paragraph), there is no disclosure of the specific use of hydrophobically modified associative polymer, or of its effect in lowering the level of salt required to see the dilution thickening effect. further, there is no disclosure of enhanced rinsing retention based on the interaction of the polymer and the electrolyte. There is no additional requirement that, on dilution, the composition remains in one phase. U.S. Patent No. 6,427,177 for Williams et al., Entitled "A Separating Multiphase Personal Wash Compositions in a Transparent or Translucent Package" (Separate multi-phase personal wash compositions in a transparent or translucent package), describes a bi-phasic or multi-phasic liquid in which, in one of the phases, high levels of electrolyte and an associative thickener can be found.

The compositions of the reference are multi-phasic prior to dilution and may or may not be mono-phasic upon dilution. They also require that much higher levels of electrolyte be used in order to form the two phases first. In contrast, the compositions of the present invention are simple phase compositions before dilution. There is no disclosure of a process to lower the level of salt required to obtain a dilution thickening effect using specific associative thickeners. Applicants have now found single phase, isotropic, undiluted compositions comprising: (1) 5% to 30% by weight of a surfactant or surfactants to cleanse the skin; (2) an amount of electrolyte from about 2% to a higher level that defines a border between mono-phasic and multi-phasic, said upper limit preferably being less than about 9%, more preferably 6% or less; (3) 0.5% to 7%, preferably 1% to 5% by weight of associative thickener; (4) 0 to 15% by weight, preferably 1% to 10% by weight of hydrotropant compound; and (5) 45% to 95% by weight of water, wherein said composition has viscosity on dilution, which is higher than the viscosity before dilution; wherein said composition has rinsing retention of more than 30% after 10 minutes as measured by the tested sample retained on a test slide as a function of rinsing time; and where, on dilution, said composition remains in a simple phase. It has been found that isotropic liquids comprising a combination of electrolyte salt and hydrophobically modified associative thickener are easily emptied from the containers and thickened upon rinsing. In addition, presumably due to a cohesive film formed on the skin (applicants do not wish to link to a theory in this regard), both easily spread over and remain on the skin, as measured by a rinse retention test. In addition, applicants have found a process for reducing the level of salt required for dilution thickening using associative thickeners of the invention. The invention relates to a process for making simple phase dilution thickening compositions comprising electrolyte. By adding defined associative thickener to said compositions, applicants have found that the required salt / electrolyte level can be lowered to obtain a dilution thickening effect. The invention also relates to single phase dilution thickening compositions both electrolyte and associative thickener. Both act synergistically to lower the salt level required for thickening to provide high viscosity retention and to provide a perceived cohesiveness for consumers as improved retention. The invention will now be described by way of example only with reference to the accompanying drawings, in which: - Figure 1 describes the effects of varying salt levels in dilution thickening compositions without the associative polymer of the invention. Examples of MgSO4 and NaCI in formulations containing 16% SLES, 3% CAPB, 0% Rewoderm LIS75 and 0% PEG400. As can be seen, the thickening of dilution in the monophasic composition starts at about 5% salt (in contrast, when the associative polymer of the invention is used, the point at which dilution thickening occurs, moves to the left or down, that is, less salt is needed); - Figure 2 describes the effect of MgS04 salt in the clear, monophasic compositions of the invention with associative polymer. The concentration effect of MgSO4 on pure and diluted samples of monophasic and biphasic formulations (16% of SLES, 3% of CAPB, 4% of Rewoderm LIS75, 11% of PEG400). The gS04 concentration labels are from pure samples. As seen, the poimer displaces the thickening phenomenon of dilution to 2% salt in single phase liquids (in contrast, compositions by Williams et al., For example, are biphasic and presumably will have higher salt levels); - Figure 3 describes the effect of associative polymer in absolute viscosity as a function of dilution ratio (Figure (a) Effects of thickened dilution in formulations of (16% SLES, 3% CAPB, 0% PEG400, 5% gS04) with and without 4% Rewoderm LIS75; (a) absolute viscosities as a function of dilution ratio, (b) proportions as a percentage of dilute to initial viscosities; - Figure 4 describes the effect of several salts (all at 4% concentration) in thickening dilution. As you can see, some salts are more effective than others. The effect of salts in pure and diluted samples of formulations containing 16% SLES, 3% CAPB, 4% Rewoderm LIS75, 11% PEG400. The salt concentration was set at 4%. All the samples were monophasic; - Figure 5 describes the effect of associative thickener on dilution thickening. Concentration effect of Rewoderm LIS75 in formulations with 16% SLES, and 3% CAPB; The samples in graph (a) also contain 4.2% MgSO4 and 11% PEG400, the samples in (b) contain 4% MgSO4 and 0% PEG400. Figure 5 (a) shows the effect with PEG and 5 (b) without PEG; and - Figure 6 summarizes the thickening effect in several associative thickeners. Effect of types or formulations of thickener with 16% of SLES, 3% of CAPB, 11% of PEG400 and 4.2% of MgSO4. All listed thickeners were soluble in this surfactant salt composition. The thickener concentrations were set at 4% except for Jaguar C13S and xanthan gum, which were reduced to 1% due to the high viscosity of the pure product. Dilution thickening is generally defined as any diluted sample having a viscosity greater than that of pure product (100: 0 product to water). In general, using relatively large amounts of salt (e.g.,> 5%), the effect is achieved. It can be seen, for example, in Figures 1 (a) and 1 (b) where formulations comprising surfactants and varying levels of MgSO4 or NaCl show dilution thickening behavior (at 66:33 dilution) starting at 5% level of Salt. Previous work has been done (for example, in US Pat. No. 6,427,177 to Williams) with so-called biphasic liquids. In that work, phase separation was seen as a function of both salt content and polyalkylene glycol content. At high levels of polyalkylene glycol (e.g., 11%), the compositions were found to be clear, isotropic, single-phase solutions at salt levels below or approximately 8%. In the present invention, it was also found that when 8% or more salt is used in the undiluted upper layer of a biphasic liquid without polyalkylene glycol and comprising associative polymer, the upper phase was turbid, cloudy and opalescent. Because it is desired to have initially clear liquids, the compositions of the invention will generally comprise less than 9% salt, preferably less than 6% salt. It should be noted that the only real upper limit is that there will be less electrolyte than the amount that would induce biphasic liquid formation because one of the ways in which the compositions of the invention are distinguished from Williams' is that they are not biphasic. . Actually, one of the advantages or improvements of the invention over the prior art is that, when liquid compositions are used monophasic, it is possible to move the point at which the thickening effect of salt dilution is seen from at least 5% (see Figures s1 (a) and 1 (b)) at levels as low as 2%. This can be seen, for example, in Figure 2, where when the associative polymer and PEG are used, the thickening begins as low as 2% salt. Another benefit of the compositions of the invention is that, in relation to compositions without thickener, the thickener imparts higher viscosity throughout the dilution process and maintains the effect of the dilution action. This is seen in Figure 3. This is, for example, without a thickener at 5% MgSO4, the absolute viscosity drops abruptly after approximately a 50:50 dilution ratio. With 4% Rewoderm LIS75 at the same salt concentration, the thickening of dilution is observed until dilution 40:60 and the fall is more gradual. The overall viscosities of the samples with thickener are also higher. Graphed as proportions in percentage between the initial and diluted viscosities of the samples, Figure 3, the thickener gave more dilution thickening effect, it is deicr, the proportions of viscosity are greater with thickener than without. Moreover, after the drop in viscosities, samples diluted with thickener were still maintained at least 10% of their initial viscosity at a 25:75 dilution.; Without Rewoderm LIS75, this viscosity ratio is only 1% at this dilution. Finally, another advantage over the technique is the "cohesiveness" provided by the thickener. This is manifested as increased retention of shower gel thickened by dilution on the skin and other surfaces (see rinse retention test and results in the examples). More specifically, the present invention relates to a novel liquid, single-phase, sotropic, composition comprising: (1) 5% to 30%, preferably 8% to 25% by weight of surfactant or surfactants; (2) from about 2% electrolyte to a higher level amount, which is both below 9% and not high enough to induce the formation of a biphasic composition, preferably, this is below about 8% , more preferably below about 6% by weight of electrolyte; (3) 0.5% to 7%, preferably 1% to 5% by weight of hydrophobically modified associative thickener, preferably not ionic but not necessarily; (4) 0 to 15%, preferably 1% to 10% by weight of hydrotropant compound; and (5) 45% to 95% by weight of water, wherein said composition has a viscosity on dilution which is greater than the viscosity before dilution; wherein said composition has rinsing retention of more than 30% after 10 minutes as measured by a retained sample on a test slide as a function of rinsing time; and where, on dilution, said composition remains in a single phase. The invention also relates to a process for lowering the level of salt required to obtain the thickening of dilution, when using a monophasic liquid composition, when using associative thickener. The compositions of the invention should contain 5% to 30% by weight of total composition of one or more anionic, amphoteric or nonionic surfactants. Anionic, amphoteric, nonionic surfactant or mixtures thereof can be used according to the present invention. Anionic surfactants which are suitable for use in accordance with the present invention include alkyl sulphates, ether alkyl sulphates, alpha olefin sulphonate, sulfosuccinates, soaps, N-acyl sarcosinates, N-acyl glutamates, N-acyl polypeptide condensates, acyl isethionates, N-acyl methyl taurates, alkyl benzene sulfonates, alcohol sulfates and phosphate esters among others. Preferred examples of anionic surfactants are sodium lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, ammonium lauryl sulfate ether, sodium lauryl sulfate ether, soap, sodium xylene sulfate, sodium phosphate, sodium olefin , Ci4-C1 B sulfonate, MEA cocoamido disodium sulfosuccinate, sodium benzene sulfonate, sodium cocyle isethionate, among others. The anionic surfactant preferably includes an alkyl sulfate ether of general formula (I): R-0- (C H 2 -C 20) nS03"(I) wherein n is 1 to 5 and R is Cg-Ci 8, preferably C1 2. Amphoteric surfactants which can be used according to the present invention include alkyl glycinates and propionates, carboxy glycinates, alkyl betaines, alkyl imidazolines sulfo betaines, alkyl polyamino carboxylates, alkyl-amino / iminopropionates and polyamino carboxy glycinates, among others. Preferred examples of amphoteric surfactants are coco-amido-propyl-betaine, sodium-coco-amphocarboxyglycinate, coco-amido, sulfo betaine, ethoxylated coco-MEA and alkyl-dimethyl-betaine among others. The preferred amphoteric surfactants are alkyl amido-propyl betaines of general formula (II): R-CO-N H- (CH2) 3-N + (CH3) 2-C H2-COO "(I I) where R has the same meaning as in Formula (I). It is especially preferred that the alkyl-amido propyl betaine is coco-amido-propyl betaine, wherein R is a fatty acid chain of coconut with 12 carbon atoms. Nonionic surfactants which may be used in accordance with the present invention include polyalkoxylated fatty alcohols and their esters, alkanolamides, polyalkoxylated and ethoxylated alkanolamides, glycosides and alkyl polyglycosides, and long chain ethoxylated amines, alkyl amines, amino -oxides, polysorbate, nonoxinoles and polyoximetes among others. Preferred examples of nonionic surfactants include polysorbate 20, nonoxinon-12 acid, lactic polyethylene-24, coconut MEA and cetyl isooctanoate, among others.

A preferred nonionic surfactant is the amino oxide of general formula (III): R1R R3-NO wherein R1 is an alkyl group of C2-2o and R2 and R3 are chain alkyls of The normal concentration of surfactant in the compositions of the present invention falls between 5% and 30% by weight based on the total weight of the composition, preferably between 8% and 25% by weight, most preferably between 10% and 20% in weigh. Among the electrolytes (organic and inorganic) which can be used according to the invention, there are halides of alkali metals, alkaline earth metals, ammonium and other metals, such as aluminum and zinc; sulfates and phosphates of alkali metals, alkaline earth metals, ammonium and other metals, such as aluminum and zinc; salts of MEA and DEA, and alkali metal silicates among others. Preferred examples of electrolytes used according to the present invention are: sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, magnesium chloride, magnesium sulfate, zinc sulfate, ammonium chloride and MEA chloride among others . As indicated above, in order to ensure that dilution thickening exists, at least about 2% salt / electrolyte is needed. However, to ensure before dilution that the As the composition is single phase, the salt / electrolyte should be used in an amount below the amount that would cause it to become biphasic. This depends on the salt and would generally be expected to be below 9% (again depending on whether the inclusion would precipitate biphasic composition formation), preferably below about 6%. As seen in the examples, the salt level will generally be about 2% to about 6% although, as noted, the upper limit is actually defined only as that amount which will cause the formation of multiphase state from the single phase. As seen in the examples (Figure 4), the particularly preferred dilution thickening salts are potassium and sodium chloride. Specifically, Figure 4 shows the viscosities of the pure and diluted samples containing various salts. At 4% salt, the ura samples containing ZnSO4, MgSO4 and Na2SO4 appear more viscous. gCI2, KCi and NaC) have little thickening effect in the initial composition of SLES, CAPB, PEG400 and Rewoderm LIS75. However, on dilution, the KCI and NaCl monovalent salts produced tremendous increases in viscosities to form highly viscous gels. ZnS04 and MgSO4 were also effective in producing large dilution thickening. Thickening dilution was observed for all soluble salts at 4%. In comparison, at 66:33 dilution, a 20-fold increase in viscosity was observed with NaCl and KCI, 3 to 6 times for MgCl 2, MgSO 4 and ZnSO 4 and a smaller increase was observed with Na 2 SO 4. The effect with CaCl2 was not true due to its solubility at 4% in the formulation, CaCl2 appeared insoluble and precipitated. As seen in Figure 5 (a), when several levels of an associative thickener were used (e.g., Rewoderm® LIS75, trade name of PEG-200 glyceryl seboate) (i.e., in composition having 16% anionic, 3 % of betaine, 11% of PEG 400 and 4.2% of MgSO4), there was a modest and linear increase in simple viscosity of pure sample. The samples diluted at 66:33 had increasing viscosities from 0 to 4% and were stabilized at 4% to 6%. The dilution thickening was observed only when at least some Rewoderm was present (ie not at 0.0%). It is also seen in Figure 5 (b), when there was no thickener present, there was no increase in viscosity in samples diluted to 0 and 1%, suggesting that at least about 2% of thickener (e.g., Rewoderm) may be necessary in the absence of PEG. In general, at least 0.5% thickener is necessary, preferably at least 2%. Associative thickeners (preferably, but not necessarily nonionic thickeners) are hydrophilic backbone (e.g., polyalkylene glycol soluble in water), essentially hydrophobically modified (for example, seboato). While not wishing to be bound by theory, it is believed that the mechanism for viscosity enhancement is due to interactions or associations of the hydrophobic groups with one another and / or with hydrophobic components of the formulations. In addition, because the thickening mechanism is independent of the loading, the polymers are preferably non-ionic and they can be used in environments high in salt. Examples of associative thickeners similar to Rewoderm® LIS75 are Rehodol® (PEG modified with tristearate) and Elfacos® T212 (carbamic acid diester of polyoxypropylene ether, polyoxyethylene of fatty alcohols derived from palm kernel oil). Other associative thickeners include ethylene glycol ether of ethylene cellulose (hydroxyethyl ethyl cellulose), such as Elfacos® CD481; or ethyl glycol methyl cellulose ether, such as Methocel® 40-10. A variety of other stifling standards in personal cleansers was also tested. Several such as Carbopol® ETD2020, Klucel® HF NF and Aculyn® 22 were salt intolerant and precipitated in the high salt formulations. Jaguar C13S and xanthan gum were compatible but due to their high molecular weight and the subsequent high viscosities generated, they were tested at only 1% or less. Figure 6 summarizes the results for different polymers. In pure samples, the polymers have variable thickening efficiency. Rheodol, Jaguar and Methocel were highly effective in thickening the pure samples. Rewoderm® LIS80 and Varonic® LIS80 have similar structures and behaved a lot like Rewoderm® LIS75. The Table below provides names, definitions and structures of various polymers, which may be used although it is understood that these are for illustrative purposes and many other polymers may have been cited.

Name Sources Definition Structure Seboato of PEG- Rewoderm Polyethylene glycol ether of tallow glyceride that is 0 200 glyceryl LIS75 conforms to the structure where RCO II RC- 0CH2CHCH2 (0CH2CH2) n0H represents the fatty acids derived from tallow DH and n has an average value of 200; The R group represents the hydrophobic Palmate of PEG-Rewoderm Derivative of polyethylene glycol of glyceride of 200 glyceryl LIS80 hydrogenated palm. It has an average of 200 hydrogenated moles of ethylene oxide. PEG Cocoate - Mixed in Polyethylene Glycol Ether of glyceryl cocoate that 0 7 glyceryl Rewoderm is generally conformed to the structure, RD - 0CH2CHCHz (0CH20Hz) n0H LIS75 and LIS80 where RCO - represents the OH fatty acids derived from coconut oil and n has a average value of 7. Triisostearate of Rheodol Triéster of isostearic acid and a PEG-160 sorbitan TWIS399C polyethylene glycol ether of sorbitol with an average of 160 moles of ethylene oxide.

Name Sources Definition Dicarbamate structure of Elfacos T212 Diaster of carbamic acid of polyoxyproylene, PPG-14 palmet-polyoxyethylene ether of the fatty alcohols R (OCHCHZ) Y (0CHzCH2) K0 - C - NH (CH2) I - 60 Hexyl derivatives of palm seed oil. CH3 has the structure where x is 60 (average), and is 14 (average) and R represents the fatty alcohols derived from palm kernel oil. Hydroxyethyl Elfacos Ethylene glycol ether ethyl cellulose ethylcellulose CD481 Hydroxypropyl Methocel 40- Ethylene glycol ether methyl cellulose methylcellulose 100 As seen in Figure 6, at a dilution of 66:33, the polymers that clearly exhibited dilution thickening behavior were Rewoderm LIS75 and LIS80, Elfacos T212 and CD481, Rheodol, Varonic LIS80 and Methocel 40-100. The Acrysol RM825 appeared to maintain or even slightly increase the viscosity. The non-hydrophobically modified polymers (Jaguar C13S and xanthan gma) did not thickened upon dilution. It can be seen that the associative nature of the polymers aids in the phenomenon of dilution thickening. In addition to the ingredients noted above, the compositions of the invention may contain hydrotropes including, but not limited to, short chain monohydric or dihydric alcohols, xylene sulfonate and hexylene glycol, which purpose is to prevent the formation of liquid crystal phases resulting from the separation of the surfactant material in the upper phase and hence increase its apparent concentration. As noted earlier, while salt is required for dilution thickening, the use of associative polymer with salt provides synergistic advantages. First, the required salt level is moved lower before the effect can occur (for example, at 2% instead of 5%). Secondly, in a rheological manner, it imparts a higher viscosity through the dilution process and maintains the effect of a greater proportion of dilution (Figure 3). Finally, as noted in the examples, the combination leads to enhanced rinsing retention. In addition to the ingredients noted above, the compositions of the invention may contain a variety of optional ingredients, such as those set out below: The compositions may comprise benefit agents. The benefit agent can be any material that has the potential to provide an effect on, for example, the skin. The benefit agent can be water-insoluble material that can protect, moisturize or condition the skin upon deposition of the compositions of the invention. These may include silicon oils and gums, fats and oils, waxes, hydrocarbons (eg, petrolatum), higher fatty acids and asters, vitamins, sunblocks. They can include any of the agents, for example, mentioned in column 8, line 31 to column 9, line 13 of the US patent no. 5, 759, 969, incorporated herein by reference in the present application. The benefit agent may also be a water-soluble material, such as glycerin, enzyme and α- or β-hydroxy acid, either alone or entrapped in an oily benefit agent. The benefit agent can be found in either the upper or lower layer, depending on its solubility and partition coefficient, for example, the oil can split in the upper layer while more water-soluble agents (eg, α-hydroxy acids) ) can go to the bottom. The compositions may comprise perfumes, sequestering agents, such as EDTA or EHDP in amounts of 0.01% to 1%, preferably 0.01% to 0.05%; dyeing, opacifying and sizing agents, such as zinc stearate, magnesium stearate, Ti02, EGMS (ethylene glycol monostearate) or styrene / acrylate copolymers. The compositions may also comprise antimicrobials, such as 2-hydroxy 4,2 ', 4'-trichlorodiphenyl ether (DP300), 3,4,4'-trichlorocarbanilide, essential oils and preservatives, such as dimethyl hydantoin (Glydant XL 1000), parabens, sorbic acid, etc. The compositions may also comprise acyl mono- or diethanol coconut amides as suds boosters and strongly ionizing salts, such as sodium chloride and sodium sulfate, may also be used to take advantage. Antioxidants such as, for example, butylated hydroxytoluene (BHT) can be advantageously used in amounts of about 0.01% or more if appropriate. Cationic conditioners, which can be used include Quatrisoft LM-200 Polyquaternium-24, Merquat Plus 3330-Polyquaternium 39; and Jaguar® type conditioners.

Examples Except in the operation and comparison examples, or where explicitly stated otherwise, all figures in this description indicating quantities or proportions of materials or reaction conditions, physical properties of materials and / or use will be understood as modified. by the word "approximately". Where used in the specification, the term "comprising" is intended to include the presence of features, integers, steps, declared components, but does not exclude the presence or addition of one or more features, integers, steps, components or groups thereof. The following examples are intended to further illustrate the invention and are not intended to limit the invention in any way. Unless indicated otherwise, all percentages are intended to be percentages by weight. In addition to compositional elements, it is critical that the compositions of the invention meet the following requirements. First, they are dilution thickeners, by which is meant that the composition, on dilution, has higher viscosity than that before dilution. Second, they should have rinse retention defined by retention of more than 30% by weight, after 10 minutes of soaking / rinsing in water, as measured by the amount of sample retained on a test slide as a function of gentle rinsing. Third, the composition must be single phase before dilution.

Methodology Raw material Trade name Lauret sodium sulfate ether (69% active) (SLES) Genapol LRO SLES Coco amido propyl betaine (30% to 39% active) Dehyton K CAPB (CAPB) Salts (MgSO4, NaCI, KCI, MgCI2, CaCI2, Na2S04, ZnS04) Poly (ethylene glycol) (400 EO's) PEG400 Formulation preparation A 75% concentrated surfactant base was first prepared with SLES, CAPB and perfume. 25% of the hole or deficit was reserved for later addition of water, thickener and salt. The final composition contained 16% SLES, 3% CAPB and 1% perfume.

Preparation of base formulation The preparation was as follows: 1) Using a beaker and water bath, water was heated to 65 ° C and mixed by starting with an overhead stirrer. 2) SLES was added to water. 3) The presence of lumps in the formulation was verified, which were debris as required. 4) The temperature was lowered and CAPB was added. 5) The composition was cooled to room temperature and the perfume was added.

Preparation of complete formulation Subsequent to the addition of thickener, polyethylene glycol and salt to the above concentrated base was done at room temperature using a top mixer until homogenized. For example, to prepare the formulation with 16% SLES, 3% CAPB, 1% perfume and 1% thickener, 1 g of thickener (adding 100% active) and 24 g of water were added to 75 g of the previous base. In the same way to prepare the formulation with 16% SLES, 3% CAPB, 1% perfume and 9% MgSO4-anhydrous, 17 g of gS04-7 H20 and 8 g of water were added. A typical formulation of the invention is as follows: Measurement of rheology Rheology measurements were conducted using a controlled stress rheometer (Rheometric Scientífic ARES) mainly. A Haake viscometer was used intermittently for rapid prototype checks. All data reported here were measured using an ARES rheometer with cone and dish or Couette geometry at 25 ° C. Cutting speed sweeps were run in logarithmic mode from 0.1 to 1 000 s' with 5 points per decade. The viscosities are cited for a fixed cutting speed at 1 0 s. "For viscosity data, viscosity measurements were conducted on balanced samples The formulations were first mixed with deionized water at appropriate proportions by weight, using bars of magnetic stirring or wrist shaker and allowed to equilibrate for 4 hours until night, all at room temperature.

Cuttings were then made as described above.

Example 1 In order to show the effect of dilution thickening and the amount of salt normally necessary to cause the effect, the applicants prepared compositions as follows: SLES 16% CAPB 3% Thickener 0 PEG 400 0 The salt levels (MgSO and NaCI) varied from 0 to 9% and the viscosities were tested both pure (100: 0) and at a dilution of 66:33. The results are shown in Figures 1 (a) and 1 (b). As discussed in the above specification, when no polymeric thickener is used, the dilution thickening effect is not seen until 5% salt is used. In contrast, the applicants tested compositions having the formulation as follows: SLES 16% CAPB 3% Rewoderm (LIS75) 4% PEG 400 11% The results under varying levels of MgSO4 are seen in Figure 2. With thickener, it can be seen that the level of salt to induce dilution thickening is as low as 2%. In this way, this thickener clearly induces a displacement.

Example 2 In order to show the difference in the dilution behavior of salts with or without thickener, the applicants tested the following formulation: SLES 16% CAPB 3% PEG 400 0% MgSo4 5% Rewoderm LIS75 4% or 0 The results are shown in Figures 3a and 3b. As can be seen clearly, the thickener imparts rheologically higher viscosity increases throughout the dilution process and maintains the effect of higher dilution. Specifically, without thickener at 5% MgSO4, the absolute viscosity drops abruptly after approximately a 50:50 dilution ratio. With 4% Rewoderm LIS75 at the same salt concentration, the dilution thickening is observed until dilution of 40:60 and the fall is more gradual. The overall viscosities of the samples with thickener are also greater. Plotted as percentage proportions between the initial and diluted viscosities of the samples, Figure 3b, the thickener gave more dilution thickening effect, ie, the viscosity ratios are higher with thickener than without. Moreover, after the drop in viscosities, the samples diluted with thickener were still maintained at least 10% of their initial viscosity at a dilution of 25:75; Without Rewoderm LIS75, this viscosity ratio is only 1% at this dilution.

Example 3 In order to show the effect of concentration and type of salt, the applicants tested the following compositions: SLES 16% CAPB 3% Rewoderm LIS75 4% PEG 400 1 1% Salt (variable) 4% The results are shown in Figure 4. Figure 4 shows the viscosities of the pure and diluted samples containing various salts. At 4% salt, the pure samples containing ZnSO4, MgSO4 and Na2SO4 appear more viscous. gCI2, KCI and NaCI have little thickening effect in the initial composition of SLES, CAPB, PEG400 and Rewoderm LIS75. However, about dilution, the KCI and NaCl monovalent salts produced tremendous increases in viscosities to form highly viscous gels. ZnS04 and gS04 were also effective in producing large dilution thickening. Thickening dilution is observed for all slurry salts at 4%. In comparison, at 66:33 dilution, a 20-fold increase in viscosity was observed with NaCl and KCI, 3 to 6 times for MgCl 2, MgSO 4 and ZnSO 4, and a smaller increase was observed with Na 2 SO. The effect with CaCl2 was not true due to its solubility at 4% in the formulation; CaCl2 seemed insoluble and precipitate.

Example 4 In order to show the effect of variable concentration of associative thickener, applicants tested the following compositions: SLES 16% CAPB 3% PEG 11% or 0 MgS04 4.0% or 4.2% Rewoderm LIS75 variable The results are shown in Figure 5. As seen in Figure 5 (a), as the amount of thickener in the composition increases without PEG, there is a modest linear increase in the viscosity of the pure sample. The viscosities increase to 0 to 4% and stabilize between 4% and 6%.

With 4.2% MgSO4 and 11% PEG400, dilution thickening was observed only when Rewoderm LIS75 was present. A similar effect was observed in formulations without PEG400. Figure 5 (b) shows trends for compositions with 4% MgSO4, 0% PEG400 and 0-4% Rewoderm LIS75. In the absence of hydrotropic PEG, the high viscosities of the pure samples come mainly from the salt (MgSO4) and the thickener seemed to contribute little to the effect. Comparing the pure samples, 0% of Rewoderm LIS75 has a viscosity of 21,500 centipoises, while those containing 1% to 4% of Rewoderm LIS75 have viscosities between 11,500 and 21,700 centipoises. The method given under rheology measurement: ARES or Haake rheometer, cutting speed of 10 s "1, 25 ° C. In the diluted samples, the increase in viscosity was not observed at 0 and 1% of Rewoderm LIS 75. dilution was significant at 2% of Rewoderm LIS75 and modest at 3% and 4% of Rewoderm LIS75.This suggests that at 4% MgS04, with and without PEG400, the concentration of Rewoderm L1S75 at more than 1% is required for thickening of dilution.

Example 5 In order to show the thickening effect of dilution of various types of thickener, applicants tested the following formulations.

SLES 16% CAPB 3% PEG400 1 1% MgS04 4.2% Thickener 4% * * except Jaguar C13S and xanthan gum, which were reduced to 1% due to high viscosity of the pure product. The results were shown in Figure 6. As seen, in the pure samples, the polymers have variable thickening efficiency. Rheodol, Jaguar and ethocel are highly effective in thickening pure samples. Rewoderm LIS80 and Varonic LIS80 have similar structures as, and behaved very similarly to, Rewoderm LIS75. At 66:33 dilution, the polymers that clearly exhibited dilution thickening behavior were Rewoderm LIS75 and LIS80, Elfacos T212 and CD481, Rheodol, Varonic LIS80 and Methocel 40-1 00. The Acrysol RM825 appeared to maintain or even slightly increase the viscosity . Polymers not hydrophobically modified (Jaguar C13S and xanthan gum) did not thickened on dilution. It appeared that the associative nature of polymers aids in the phenomenon of dilution thickening.

Example 6 - Rinsing retention The enhanced retention of the dilution thickening effect was clearly observed during a hand wash with the samples. The samples containing the associative thickener of the invention formed a sticky film on the skin that persisted for a long time during the wiping, while the samples with only salts rinsed more quickly. This retention effect was quantified by simulating the gel application and rinsing process. The method was established to capture the retention effect as a function of time. The procedure is illustrated as follows: 1) Mark an area of 7.62 cm x 6.35 cm (3 in x 2.5 in) on a glass microscope slide 2) Record the weight of the microscope slide 3) Place approximately 0.5 g of sample on the slide, spread evenly to cover the marked area and record the weight of the slide and the sample. 4) Fill a 62.5 ml (2 oz.) jar with 50 g of deionized water and place a magnetic stir bar on the bottom of the slide. jar 5) Place the slide in the jar with water so that the sample area is completely submerged under water and the slide does not touch any wall, bottom of the jar or stir bar 6) Shake the water in the jar using a magnetic stirrer at a speed set at 4 7) Remove the slide from the jar at fixed time intervals (5 minutes, 10 minutes, 30 minutes, 60 minutes and 2 hours), and remove excess water from the slide but without touching the sample area using Kim wipes 8) Record the weight of the sample and slide 9) Return the sample to the jar with water to the same position as in the step (5) 10) Repeat steps (5) to (8) during the remaining time intervals or until no sample residue remains on the slide. Table 1 below lists the results for the samples tested. The samples each contained 16% SLES, 3% CAPB and 0.0125% water-soluble blue dye (Acid Blue 9 or Erioglaucine disodium salt); the amount of salt, thickener and PEF400 were varied; all these compositions were monophasic, isotropic and transparent. The rinse retention was harvested as a percentage of the remaining sample on the slide after "rinsing" or immersed in the stirred water, for fixed amounts of time. Although the excess water was dried on the slides before weighing, any water absorbed by the samples was not removed. Hence, some of the percentages may be greater than 100% (for example, sample 6B). In all the samples where thickeners were not added, the samples were rinsed mainly after 5 minutes of agitation; Trace amounts remained on the slides after 10 minutes and the slides were wiped completely after 30 minutes. When thickener was used, approximately half of the samples were still retained after 10 minutes of rinsing: significant amounts were still visibly stuck after 30 minutes and most of the samples were rinsed between 1 to 2 hours of soaking and stirring. Comparing levels of 1% and 4% of Rewoderm LIS75 (although salt concentrations differed), higher levels of thickeners prolonged the retention of samples during rinsing.

In addition, PEG400 did not affect the retention trend.

Table 1: Compositions and results for gel retention test Sample Composition (16% SLES, Percentage of sample retained on slides 3% CAPB, +) as a function of "rinse" time MgS04 Rewoderm PEG 5 10 30 60 20 LIS75 400 minutes minutes minutes minutes 6A 4% 0% 0% 28% 3% 0% 6B 4% 4% 0% 1 3% 102% 33% 6C 4% 4% 11% 85% 57% 18% 21% 3% 6D 4% 0% 1% 43% 3% 0% 0% 6E 6% 0% 0% 22% 5% 0% 6F 6% 1% 0% 47% 36% 14% 8% 2%

Claims (10)

1 . A process for moving lower the level of salt required to produce thickening effect of dilution of a composition, said process comprises adding to the composition 0.5% to 7% by weight of hydrophobically modified associative thickener, wherein the composition comprises an isotropic composition , single phase, comprising: (1) 5% to 30% by weight of a surfactant or surfactants to clean the skin; (2) more than about 2% at the electrolyte level, so that the upper limit will not cause the isotropic composition to become biphasic or multiphasic; (3) 0.5% to 7% by weight hydrophobically modified associative thickener; (4) 1 to 15% by weight of hydrotropant compound; and (5) 45% to 95% by weight of water, wherein the composition has a viscosity over the dilution which is greater than the viscosity before dilution; wherein the composition has rinse retention of more than 30% by weight after 10 minutes as measured by a sample retained on a test slide as a function of rinsing time; and where, on dilution, the composition remains in a simple phase.

2. A process according to claim 1, wherein the associative thickener comprises a polymer with a hydrophobic backbone modified by hydrophobic groups.

3. A process according to claim 1, wherein the associative thickener has a hydrophobically modified hydrophilic skeleton.

4. A process according to claim 3, wherein the modified hydrophilic backbone comprises water-soluble polyalkylene glycol units.

5. A process according to any of the preceding claims, wherein the associative thickener is non-ionic.

6. A process according to any of the preceding claims, wherein the hydrotrope is a monohydric or dihydric alcohol, xylene sulfonate or hexylene glycol.

7. An isotropic, single phase composition comprising: (1) 5 to 30% by weight of a surfactant or surfactants to clean the skin; (2) more than about 2% at the electrolyte level, so that the upper limit will not cause the isotropic composition to become biphasic or multiphasic; (3) 0.5 to 7% by weight of hydrophobically modified associative thickener; (4) 1 to 15% by weight of hydrotropant compound; and (5) 45 to 95% by weight of water, wherein said composition has a viscosity on dilution, which is greater than the viscosity before dilution; wherein said composition has rinse retention of more than 30% by weight after 10 minutes as measured by a sample retained on a test slide as a function of rinsing time; and where, on dilution, said composition remains in a simple phase.

8. A composition according to claim 7, wherein said electrolyte is selected from the group consisting of magnesium salts, sulfate salts and chloride salts.

9. A composition according to claim 7 or 8, having less than about 9% electrolyte.

10. A composition according to claim 7, 8 or 9, having less than about 6% electrolyte. eleven . A composition according to any one of any of claims 7 to 10, comprising 1 to 5% thickener. 12. A composition according to any of claims 7 to 11, wherein the thickener comprises a polymer with a hydrophobic backbone modified by hydrophobic groups. 13. A composition according to any of claims 7 to 12, wherein said thickener is non-ionic. 14. A composition according to any of claims 7 to 13, comprising 1 to 10% hydrotrope. 15. A composition according to any of claims 7 to 14, wherein the hydrotrope is polyalkylene glycol.