Method for determining flushing performance

Abstract

A method for measuring the rinsing performance of a composition from a human surface, comprising the steps of: i) providing a cosmetic treatment composition; ii) applying the composition of (i) to the surface; iii) rinsing the surface with water; iv) collecting the rinse water; v) optionally repeating steps iii)-iv); and vi) measuring the turbidity of the collected rinse water; until a constant turbidity is achieved.

Description

Technical Field

[0001] The present invention relates to a method for determining the rinsing performance of compositions having particular application in the field of hair care. Background Art

[0002] Many products formulated for use on surfaces are designed to be rinsed off during use. Such products include shampoos and conditioning compositions for use on hair. These can be used as part of a hair care regimen, such as daily washing and conditioning. These products typically deposit benefit agents, such as silicones, onto the hair surface. Other leave-on compositions deposit benefit agents onto the hair, which remain on the hair until the next time the hair is washed.

[0003] The rinsing of a composition from a surface is an important phenomenon. It can influence the way a consumer perceives the performance of a product or makes a decision about whether to stop or continue rinsing. The rinsing properties of a hair treatment composition influence the length of time a consumer rinses their hair and, therefore, effectively directly influences the amount of water a consumer uses when using a rinse-off product.

[0004] It is known to measure the amount of foam and correlate it with rinse performance.

[0005] WO 15 / 018853 discloses cosmetic compositions containing silicones to facilitate rinsing. Methods of measuring the effect on the rinsing phase include measuring the time required to remove the foam, or the number or amount of water required.

[0006] WO 05 / 107699 discloses foaming cleansers with suspended particles. A test is described for determining the ability of the foam to be rinsed from the hands until the foam disappears.

[0007] GB 2208297 discloses liquid detergent compositions for laundry, household cleaning, hair and body. A rinseability test is employed using a measured amount of water until no surfactant foam is visible.

[0008] However, we have discovered that foam tracking methods have several drawbacks. Foam is sensitive to factors such as water temperature, flow rate, and time. For example, foam volume can vary with these variables, making these methods less accurate and difficult to reproduce. Different operators may visually assess the amount of foam differently.

[0009] IN 01452KO2013 discloses a quantitative method for measuring the rinseability of cleansing formulations by measuring the conductivity of the wash water. The formulation is applied to the skin and the wash water is applied in duplicate. A standard conductivity score card is then used to determine the rinseability rating of the formulation.

[0010] US2002 / 037267 discloses a foaming cleansing composition that is a transparent gel. Turbidity is used to measure the clarity of the composition itself. The quality of the foam during rinsing is studied as a slippery film that is easily removed from the hands.

[0011] US5928657 discloses a cosmetic composition for cleansing the skin and improving the rinseability of an oily gel composition. Turbidity is used to characterize the behavior of the gel composition itself after dispersing the gel in water in a flask.

[0012] US2017 / 145669 discloses a shower for use in a human enclosure, wherein body wash, shampoo / conditioner, or hair dye is applied thereto and then rinsed. To conserve water, the shower includes a drainage system that includes a pollution sensor consisting of a turbidity sensor that measures suspended solids in the water by measuring the amount of light transmitted through the wastewater in the drain pipe. If the pollution sensor detects a specific level of soap / shampoo / detergent / conditioner or hair dye in the wastewater, the wastewater is directed to the sewer, while if there is no soap / shampoo / detergent / conditioner or hair dye in the wastewater (in which case the turbidity sensor will detect a constant turbidity), the clean wastewater is directed to the water circulation system.

[0013] CN102090852A discloses a method for saving water in a shower room, which includes a shower collector and a water quality detection instrument that continuously monitors the turbidity of the water in the collector. If the measured turbidity of the collected water is greater than 0.4 NTU, the shower water continues to run, and if the measured turbidity is (continuously) less than 0.4 NTU, an alarm is generated.

[0014] Despite the prior art, there remains a need for a method for determining the rinsing properties of a composition that is accurate, reliable, and accessible, and that can be performed quickly and easily.

[0015] We have found that by measuring the turbidity of the water used to rinse the composition from the hair surface during or after rinsing, we can provide a reliable and achievable way of predicting the rinsing performance of the composition with excellent accuracy. Using this method it is possible to determine when no more composition is being removed from the hair and therefore determine the endpoint of rinsing. Summary of the Invention

[0016] In a first aspect, the present invention provides a method of measuring the rinsing performance of a composition from a human surface, comprising the steps of:

[0017] i) providing a cosmetic treatment composition;

[0018] ii) applying the composition of (i) to a surface;

[0019] iii) Rinse the surface with water;

[0020] iv) collecting the flushing water;

[0021] v) optionally repeating steps iii)-iv); and

[0022] vi) measuring the turbidity of the collected flushing water,

[0023] until a constant turbidity is reached and

[0024] Repeat steps (i) through (vi) for a second treatment composition, and compare the rinsing performance of the first treatment composition and the second treatment composition to determine the relative rinsing rates of the first treatment composition and the second treatment composition.

[0025] The preferred method includes the step of correlating the turbidity of the collected rinse water with the amount of water used to rinse the surface.Preferably, the turbidity of the rinse water is compared with the turbidity of pure water.

[0026] Preferably, the method comprises repeating steps iii) to vi) at set time intervals. Preferably, the time interval is 4 to 120 seconds, more preferably 5 to 60 seconds, and most preferably 5 to 20 seconds. Preferably, steps iii) to iv) are repeated until the turbidity reaches zero.

[0027] The surface is rinsed with water. The water can be applied as a stream or as discrete amounts (e.g., aliquots). Preferably, a stream of water is used, preferably with a constant flow rate. The temperature of the water can also affect the rate of rinsing and is preferably kept constant throughout the method.

[0028] Constant turbidity is when the turbidity remains approximately constant. This is indicated by the formation of a plateau in the turbidity variation over successive measurements. There may still be some variation, but these variations are small enough to indicate that only very small amounts of the composition are being removed.

[0029] Constant turbidity can be determined by recording the time at which consecutive turbidity measurements do not differ significantly from each other.

[0030] Constant turbidity indicates the endpoint of rinsing of the composition from the human surface. DETAILED DESCRIPTION

[0031] method

[0032] The method of the present invention measures the rinsing performance of a composition. Rinse performance is related to the amount of water required to rinse the composition from a surface.

[0033] The composition is a cosmetic composition. Cosmetic compositions, such as personal care compositions, are intended for application to the human body, in particular to the skin or hair. Preferably, the composition is selected from hair compositions (such as hair cleansing compositions, hair conditioning compositions or hair styling compositions) and skin compositions (such as skin cleansing compositions or skin conditioning compositions).

[0034] Advantageously, the method of the present invention can be used to compare the rinsing performance of different compositions, for example a composition before and after modification of the composition. This is achieved by performing the method using a first treatment composition and then performing the method using a second treatment composition.

[0035] Preferably, the method comprises repeating steps (i) to (vi) with a second treatment composition and comparing the rinsing performance of the first and second treatment compositions to determine the relative rinsing rates of the first and second treatment compositions. The composition having a greater reduction in turbidity after rinsing rinses faster from the surface and requires less water to rinse from the surface.

[0036] Turbidity can be measured using any suitable technique. A preferred method includes using a turbidity meter, such as a Turbiscan TLab Expert. Turbidity is suitably measured relative to clear water.

[0037] Treatment composition

[0038] The composition is preferably formulated as a rinse-off composition.

[0039] Preferably, the composition is structured. By structured it is meant that it comprises an orientation of molecules forming a gel phase or a lamellar phase.

[0040] The composition is preferably a hair treatment composition.

[0041] Rinse-off hair treatment compositions for use in the present invention are preferably selected from shampoos and conditioners, most preferably conditioners.

[0042] Compositions for use in the methods of the present invention are preferably formulated as conditioners for use in treating the hair (typically after shampooing) and subsequently rinsing.

[0043] Preferred conditioners comprise a conditioning matrix.The conditioning matrix preferably forms a gel phase.

[0044] The treatment composition used in the method of the present invention preferably comprises a conditioning agent. The conditioning agent is preferably selected from cationic surfactants, used alone or in admixture.

[0045] Cationic surfactants useful in the compositions employed in the methods of the present invention contain amino or quaternary ammonium hydrophilic moieties which possess a positive charge when dissolved in an aqueous composition.

[0046] Examples of suitable cationic surfactants are those corresponding to the following formula:

[0047] [N(R1)(R2)(R3)(R4)] + (X) -

[0048] wherein R1, R2, R3 and R4 are independently selected from (a) aliphatic groups of 1 to 22 carbon atoms, or (b) aromatic, alkoxy, polyoxyalkylene, alkylamido, hydroxyalkyl, aryl or alkaryl groups having up to 22 carbon atoms; and X is a salt-forming anion, such as those selected from halogen (e.g., chloride, bromide), acetate, citrate, lactate, glycolate, phosphate, nitrate, sulfate and alkyl sulfate.

[0049] In addition to carbon and hydrogen atoms, aliphatic groups may also contain ether linkages and other groups such as amino groups. Longer chain aliphatic groups, such as those of about 12 carbons or greater, may be saturated or unsaturated.

[0050] The most preferred cationic surfactants for use in the compositions of the present invention are those having an alkyl chain length of C8-C 14 Monoalkyl quaternary ammonium compounds.

[0051] Suitable examples of such materials correspond to the formula

[0052] [N(R5)(R6)(R7)(R8)] + (X) -

[0053] wherein R5 is a hydrocarbon chain having from 8 to 14 carbon atoms or a functionalized hydrocarbon chain having from 8 to 14 carbon atoms and containing an ether, ester, amido or amino moiety as a substituent or as a bond within the radical chain, and R6, R7 and R8 are independently selected from (a) a hydrocarbon chain having from 1 to about 4 carbon atoms, or (b) a functionalized hydrocarbon chain having from 1 to about 4 carbon atoms and containing one or more aromatic, ether, ester, amido or amino moieties as a substituent or as a bond within the radical chain, and X is a salt-forming anion such as those selected from halogens (e.g., chloride, bromide), acetate, citrate, lactate, glycolate, phosphate, nitrate, sulfate and alkyl sulfate.

[0054] The functionalized hydrocarbyl chain (b) may suitably contain one or more hydrophilic moieties selected from alkoxy groups (preferably C1-C3 alkoxy groups), polyoxyalkylene groups, alkyl esters and combinations thereof.

[0055] Preferably, the hydrocarbon chain R1 has 12 to 14 carbon atoms, most preferably 12 carbon atoms. They can be derived from source oils containing a large amount of fatty acids with the desired hydrocarbon chain length. For example, fatty acids from palm kernel oil or coconut oil can be used as C8 to C 12 Origin of the hydrocarbon chain.

[0056] Typical monoalkyl quaternary ammonium compounds of the above formula used in the compositions of the present invention include:

[0057] (i) Lauryltrimonium chloride (commercially available as Arquad C35 from Akzo); Cocodimethylbenzylammonium chloride (commercially available as Arquad DMCB-80 from Akzo)

[0058] (ii) a compound of the formula:

[0059] [N(R1)(R2)((CH2CH2O) x H)((CH2CH2O) y H] + (X) -

[0060] in:

[0061] X+y is an integer from 2 to 20;

[0062] R1 is a hydrocarbyl chain having 8 to 14, preferably 12 to 14, most preferably 12 carbon atoms and containing an ether, ester, amide or amino moiety as a substituent or as a bond in the radical chain;

[0063] R2 is C1-C3 alkyl or benzyl, preferably methyl, and

[0064] X is a salt-forming anion, such as those selected from halogen (eg, chloride, bromide), acetate, citrate, lactate, glycolate, phosphate, nitrate, sulfate, methylsulfate, and alkylsulfate.

[0065] Suitable examples are PEG-n lauryl ammonium chloride (where n is the PEG chain length), such as PEG-2 cocomethyl ammonium chloride (commercially available as Ethoquad C12 from Akzo Nobel); PEG-2 cocobenzylammonium chloride (commercially available as Ethoquad CB12 from Akzo Nobel); PEG-5 cocomethyl ammonium methylsulfate (commercially available as Rewoquat CPEM from Rewo); PEG-15 cocomethyl ammonium chloride (commercially available as Ethoquad C / 25 from Akzo).

[0066] (iii) a compound of the formula:

[0067] [N(R1)(R2)(R3)((CH2) n OH)] + (X) -

[0068] in:

[0069] n is an integer from 1 to 4, preferably 2;

[0070] R1 is a hydrocarbyl chain having 8 to 14, preferably 12 to 14, most preferably 12 carbon atoms;

[0071] R2 and R3 are independently selected from C1-C3 alkyl, and preferably methyl, and

[0072] X - are salt-forming anions, for example those selected from halogens (eg chloride, bromide), acetate, citrate, lactate, glycolate, phosphate, nitrate, sulfate, alkylsulfate.

[0073] A suitable example is lauryl dimethyl hydroxyethyl ammonium chloride (commercially available as Prapagen HY from Clariant).

[0074] Mixtures of any of the foregoing cationic surfactant compounds may also be suitable.

[0075] Examples of suitable cationic surfactants for use in the hair compositions of the present invention include cetyltrimethylammonium chloride, behenyltrimethylammonium chloride, cetylpyridinium chloride, tetramethylammonium chloride, tetraethylammonium chloride, octyltrimethylammonium chloride, dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, octyldimethylbenzylammonium chloride, decyldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride, didodecyldimethylammonium chloride, dioctadecyldimethylammonium chloride, tallowtrimethylammonium chloride, coconuttrimethylammonium chloride, and their corresponding hydroxides. Other suitable cationic surfactants include those having the CTFA designations Quaternium-5, Quaternium-31, and Quaternium-18. Mixtures of any of the foregoing materials may also be suitable. A particularly useful cationic surfactant is cetyltrimethylammonium chloride, which is commercially available from Henkel as, for example, DEHYQUART.

[0076] The cationic surfactant is preferably present in an amount of from 0.01 to 10 wt %, more preferably from 0.05 to 5 wt %, most preferably from 0.1 to 2 wt % of the total composition.

[0077] Preferred conditioners comprise a conditioning gel phase.Such conditioners and their methods of preparation are described in WO2014 / 016354, WO2014 / 016353, WO2014 / 016352 and WO2014 / 016351.

[0078] The conditioning compositions may also contain other optional ingredients. Such ingredients include, but are not limited to, fatty materials, deposition polymers and other conditioning agents.

[0079] The conditioner composition preferably additionally comprises a fatty material.The combined use of fatty material and cationic surfactant in conditioning compositions is believed to be particularly advantageous since this leads to the formation of a structured lamellar or liquid-crystalline phase in which the cationic surfactant is dispersed.

[0080] "Fatty material" refers to fatty alcohols, alkoxylated fatty alcohols, fatty acids, or mixtures thereof.

[0081] Preferably, the alkyl chains of the fatty material are fully saturated.

[0082] Representative fatty materials contain 8 to 22 carbon atoms, more preferably 16 to 22 carbon atoms. Examples of suitable fatty alcohols include cetyl alcohol, stearyl alcohol, and mixtures thereof. The use of these materials is also advantageous because they contribute to the overall conditioning properties of the composition.

[0083] Alkoxylated (e.g., ethoxylated or propoxylated) fatty alcohols having from about 12 to about 18 carbon atoms in the alkyl chain can be used in place of or in addition to the fatty alcohols themselves. Suitable examples include ethylene glycol cetyl ether, polyoxyethylene (2) stearyl ether, polyoxyethylene (4) cetyl ether, and mixtures thereof.

[0084] The amount of fatty material in the conditioner is suitably 0.01-15% by weight, preferably 0.1-10% by weight, more preferably 0.1-5% by weight of the total composition. The weight ratio of cationic surfactant to fatty alcohol is suitably 10:1-1:10, preferably 4:1-1:8, optimally 1:1-1:7, for example 1:3.

[0085] Other conditioning ingredients include esters of fatty alcohols and fatty acids, such as cetyl palmitate.

[0086] Conditioning compositions for use in accordance with the present invention may preferably comprise a miscellar structured liquid.

[0087] The pH of conditioners comprising the compositions of the present invention is preferably from 3 to 5. More preferably, the pH of the composition is from 4.5 to 5.5.

[0088] Viscosity reducers

[0089] Preferably, the method of the present invention comprises the step of adding a viscosity reducing agent to the neat treatment composition to reduce the viscosity.

[0090] Preferred viscosity reducing agents are hydrophobically modified anionic polymers.Preferably, the hydrophobically modified anionic polymers are acrylate or methacrylate polymers.

[0091] Preferably, the hydrophobic modification comprises alkylation.Preferably, the alkyl group comprises 6 to 30 carbons, more preferably C12 to C30, even more preferably 16 to 28, most preferably 18 to 24 carbons.

[0092] Preferred polymers are sold by Rohm & Haas under the trade name Aculyn, with Aculyn 28 being the most preferred. TM .

[0093] The polymer is preferably added at a level of from 0.01 to 5%, more preferably from 0.02 to 05%, even more preferably from 0.03 to 4%, most preferably from 0.05 to 4% by weight of the total weight of the hair treatment composition.

[0094] Preferably, the surface is a hair surface.

[0095] Example

[0096] Embodiments of the invention will now be illustrated in the following examples, in which amounts are given by weight of the total composition unless otherwise stated.

[0097] Example 1: Compositions A, B, C and D for use in the method of the present invention

[0098] The following hair conditioner composition was prepared:

[0099] Compositions AD are hair conditioners. Compositions A and C contain Acrylates / Beheneth-25 Methacrylate Copolymer, which increases the rate of rinsing from the hair surface.

[0100] Table 1: Composition of Conditioners A and B used in the process of the present invention

[0101] A B Element Amount [wt%] Amount [wt%] Cetearyl Alcohol 3.2 3.2 Behenyltrimethylammonium chloride 2.3 2.3 Conditioning silicone 1.4 1.4 spices 0.6 0.6 Acrylates / Beheneth-25 Methacrylate Copolymer 0.25 - UV fluorescent agent (Tinopal CBS-X, from BASF) 0.1 0.1 preservative 0.1 0.1 water to 100 to 100

[0102] Table 2: Composition of Conditioners C and D for Use in the Method of the Invention

[0103]

[0104]

[0105] Conditioner AD was prepared using the following method:

[0106] 1. Add water to a suitable container, add lactic acid (if present) and copolymer (if present), and heat the container to 80° C. Add UV phosphor.

[0107] 2. Cetearyl alcohol is then added to the formulation along with the tertiary amine salt (if present).

[0108] 3. Add behentrimethylammonium chloride (if present) at 80°C and mix the resulting mixture.

[0109] 4. Then stop heating and add quenching water.

[0110] 5. The mixture was then cooled to below 40°C and the remaining materials were added.

[0111] 6. Finally, the formulation was mixed under high shear on a Silverson mixer at 5000 rpm for 5 minutes.

[0112] Example 2: Turbidity measurement of rinse water from hair treated with compositions AD

[0113] The hair used in the following examples was dark brown European hair in 5g 10" switches.

[0114] 1. Before starting any treatment, pre-wash the hair switches with 14% SLES-1EO solution to remove any surface contaminants. Each hair switch is treated with 0.1 mL of solution / g hair and rubbed for 30 seconds, then washed in warm water (35°C-40°C, flow rate 4 L min -1 Remove excess water by passing the switch between fingers and thumb under light pressure.

[0115] 2. Apply 2.5g of Conditioner A, B, C or D to the hair switch and spread evenly over the entire surface of the switch.

[0116] 3. Secure the hair switch to the clamp using the metal clip and the container located under the hair switch.

[0117] 4. Water is applied to the hair switch (at a flow rate of approximately 1 L / min) and collected in a container. Water is applied to the hair switch at the following time points (10 / 20 / 25 / 30 / 35 and 40 seconds), and the water that runs off the hair switch during each time point is collected in a separate glass jar. At each time point, the stopwatch and water flow are stopped to allow the water to collect and a new container is placed under the hair switch.

[0118] Three replicates were performed for each formulation (using a new hair switch for each replicate).

[0119] The turbidity of the collected rinse water samples was measured using a Turbiscan TLab Expert at 25° C. The values from the Turbiscan were obtained as ΔT relative to the clear water.

[0120] The results are given in Table 3 below.

[0121] Table 3: Turbidity / ΔT of rinse water from hair treated with compositions AD (average of three replicates)

[0122]

[0123]

[0124] In summary, the method of the present invention enables accurate measurement of the rinsing performance of different compositions.

Claims

1. A method for measuring the rinsing performance of a composition from a human surface, comprising the steps of: i) providing a first treatment composition which is a cosmetic treatment composition; ii) applying the composition of i) to the surface; iii) rinsing the surface with water; iv) collecting the flushing water; v) repeating steps iii)-iv); and vi) measuring the turbidity of the collected flushing water; until a constant turbidity is reached and Repeat steps i) through vi) for a second treatment composition, and compare the rinsing performance of the first treatment composition and the second treatment composition to determine the relative rinsing rates of the first treatment composition and the second treatment composition.

2. The method of claim 1, wherein steps iii) to iv) are repeated at time intervals.

3. The method of claim 1 or 2, wherein steps iii) to iv) are repeated at time intervals of 4 to 120 seconds.

4. The method of claim 1 or 2, wherein the water is a stream of water.

5. A method as claimed in claim 1 or 2, comprising the step of correlating the rinse water collected in step iv) with the amount of water used to rinse the surface.

6. The method of claim 1 or 2, wherein the surface is selected from human hair and skin.

7. The method of claim 1 or 2, wherein the composition is a structured composition comprising molecular orientations forming a gel phase or a lamellar phase.

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