Transparent liquid cleaning composition

Abstract

The present invention relates to a liquid cleaning composition comprising a soap and an amphoteric surfactant in a selected weight ratio, and a selected non-soap anionic surfactant. The composition has a transparency of less than 100 NTU when measured at a temperature in the range of 4-25 DEG C and a viscosity in the range of 2,500 to 10,000 cps when measured at 25 DEG C, and the composition provides an excellent foam.

Description

Technical Field

[0001] The present invention relates to a transparent liquid cleaning composition. In particular, the present invention relates to a liquid cleaning composition that is transparent at low temperatures (e.g., 4 - 25 °C). Background Art

[0002] WO11057909 (Unilever) discloses a mild, substantially isotropic skin cleaning solution which has been found to be able to suspend insoluble components and provide a large amount of foam. The detergent is formulated with synthetic anionic surfactants and a specific ratio of carboxylic acid and hydrophobically modified crosslinked acrylate copolymer. It has been found that the combination of carboxylic acid and acrylate polymer provides a synergistic effect on the zero shear viscosity at 25 °C within a specific pH value and copolymer / acid concentration ratio range.

[0003] IN377416 (ITC Limited) discloses a transparent liquid detergent composition. In particular, IN377416 discloses a transparent liquid detergent composition comprising (a) at least one free fatty acid; and (b) at least one anionic surfactant; and a method for preparing the composition.

[0004] FR3065874 discloses a cosmetic composition in the form of a liquid, transparent hygiene product having a pH of less than 8, characterized in that it comprises, as active ingredients: - from 1% to 10% by mass of at least one fatty acid, - from 0.5% to 8% by mass of at least one fatty acid neutralizing agent that reacts with the fatty acid to form a soap, - from 1% to 25% by mass of at least one major amphoteric surfactant belonging to the betaine family, - from 0.5% to 6% by mass of at least one minor amphoteric and / or anionic surfactant, the other ingredients of the composition consisting of those ingredients permitted in the cosmetic field.

[0005] Despite attempts made so far, it remains a challenge to provide a liquid cleaning composition that is transparent at lower temperatures (e.g., 4 - 25 °C). Additionally, in the presence of soap and thus within an alkaline pH range, delivering such a transparent composition while still having sufficient foaming is challenging. Furthermore, providing such a transparent composition with an appropriate viscosity (e.g., 2500 to 10,000 cps) is also challenging.

[0006] It has been found that when the composition comprises a selected weight ratio of soap and amphoteric surfactant and a selected anionic surfactant, the composition exhibits a transparency of less than 100 nephelometric turbidity units (NTU) at lower temperatures (e.g., 4 - 25 °C). When measured at 25 °C, the composition exhibits a viscosity in the range of 2,500 - 10,000 cps. Excellent foaming properties are also obtained, as demonstrated by high foaming. Summary of the Invention

[0007] The present invention relates to a transparent liquid cleaning composition comprising:

[0008] a. Soap; and

[0009] b. An amphoteric surfactant,

[0010] wherein the soap and the amphoteric surfactant are present in a weight ratio of less than or equal to 2:1,

[0011] wherein when measured at a temperature of 4 - 25 °C, the transparency of the composition is less than 100 NTU; and

[0012] wherein when measured at 25 °C, the viscosity of the composition is in the range of 2,500 - 10,000 cps;

[0013] wherein the composition further comprises 1 - 25% by weight of a non - soap anionic surfactant selected from alkyl sulfates, alkyl ether sulfates, α - olefin sulfonates, and mixtures thereof. Detailed Description

[0014] Any feature of one aspect of the present invention can be used in any other aspect of the present invention. The term "comprising" means "including", but not necessarily "consisting of" or "constituted by". In other words, the listed steps or options need not be exhaustive. Unless in the operating and comparative examples, or where otherwise expressly stated, all numbers in this specification indicating amounts of materials or reaction conditions, physical properties of materials, and / or uses should be understood to be modified by the word "about". Numerical ranges expressed in the format "from x to y" should be understood to include x and y. When multiple preferred ranges are described in the format "from x to y" for a particular feature, it should be understood that all ranges combining different endpoints are also contemplated. Unless otherwise specified, amounts used herein are expressed as weight percentages based on the total weight of the composition and may be abbreviated as "wt%". The use of any and all examples or exemplary language, such as "for example", provided herein is only intended to better illustrate the invention and in no way limits the scope of the invention as otherwise claimed. As used herein, the term "skin" preferably refers to the skin on any part of the body, such as the face, neck, chest, back, arms, armpits, hands, legs, buttocks, and scalp.

[0015] The term "transparent" as used herein preferably means that the transparency of the liquid composition is less than 100, preferably less than 75, more preferably less than 50, and even more preferably less than 25 nephelometric turbidity units (NTU).

[0016] Thus, the transparent liquid cleaning composition according to the present invention (the "composition") comprises:

[0017] a. Soap; and

[0018] b. An amphoteric surfactant,

[0019] wherein the soap and the amphoteric surfactant are present in a weight ratio of less than or equal to 2:1,

[0020] wherein when measured at a temperature in the range of 4 - 25 °C, the transparency of the composition is less than 100 NTU; and

[0021] wherein when measured at 25 °C, the viscosity of the composition is in the range of 2,500 - 10,000 cps.

[0022] Cleaning composition

[0023] The composition is suitable for the purpose of cleaning surfaces (such as the skin). Typically, the composition is used in a suitable amount, such as 5 to 10 mL; and is applied to the skin in a suitable manner (usually by hand), or alternatively, a sponge, loofah or similar material and a large amount of water are used to generate foam; and it is rinsed off with water to clean the surface, such as the skin.

[0024] Soap

[0025] The composition contains soap. Soap is a salt of a fatty acid, which also acts as an anionic surfactant. When used in a cleaning composition, soap is known to improve the skin feel of the composition. However, due to its alkaline pH, soap is usually caustic to the skin and may cause a dry or itchy feeling. Therefore, although soap may provide these preferred benefits, its use in large amounts usually results in less preferred effects. Thus, soap is used in a moderate amount in the present invention. However, even in a moderate amount similar to that described herein, the presence of soap tends to cause opacity of the liquid cleaning composition. In this case, one way to obtain a transparent composition is to remove the soap, but this results in the loss of the benefits provided by the soap. Therefore, it remains a challenge to provide a transparent and appropriately viscous composition (although it contains soap). The present invention solves this problem.

[0026] Soap is a salt of a fatty acid having a carbon chain length of 6 - 30, preferably 8 - 14, more preferably 10 - 12. Thus, sodium or potassium salts of fatty acids (such as caprylic acid, caproic acid, lauric acid, myristic acid and palmitic acid) are particularly suitable soaps for use in the present invention. Examples of soaps include potassium laurate, potassium myristate, potassium palmitate, sodium laurate, sodium myristate, sodium palmitate. Among the sodium or potassium salts of fatty acids, the potassium salts of fatty acids are preferred.

[0027] Preferably, the composition comprises from 0.01 to 7% by weight, more preferably from 0.05 to 6% by weight, even more preferably from 0.01 to 5% by weight, still more preferably from 0.05 to 4% by weight, yet more preferably from 0.1 to 2% by weight, and still more preferably from 0.1 to 1% by weight of soap.

[0028] Amphoteric surfactant

[0029] The composition further comprises an amphoteric surfactant. They provide foam enhancement and improve the sensory properties of the composition. Preferably, the amphoteric surfactant is selected from betaines such as cocamidopropyl betaine (CAPB), sulfobetaines, cocoyl amphoacetates and mixtures thereof. More preferably, the amphoteric surfactant is selected from betaines, sulfobetaines and mixtures thereof. Even more preferably, the selected amphoteric surfactant is CAPB.

[0030] Preferably, the composition comprises from 1 to 5% by weight, more preferably from 1.5 to 4.5% by weight, even more preferably from 2 to 4% by weight, still more preferably from 2 to 3.5% by weight, and yet more preferably from 2.5 to 3% by weight of the amphoteric surfactant.

[0031] Ratio of soap to amphoteric surfactant

[0032] The composition comprises soap and an amphoteric surfactant, wherein the weight ratio of soap to amphoteric surfactant is less than or equal to 2:1. Preferably, the weight ratio of soap to amphoteric surfactant is less than 2:1. For example, if potassium laurate is the soap and CAPB is the amphoteric surfactant, they are present in a weight ratio of 2:1 or less, such as 1.75:1, more preferably less than 1.5:1, even more preferably less than 1.25:1, still more preferably 1:1. When the weight ratio of soap to amphoteric surfactant is greater than 2:1, i.e., when not according to the present invention, it has been found that a liquid cleaning composition with the desired transparency and / or viscosity is not obtained.

[0033] It has been found that when the weight ratio of soap to amphoteric surfactant is as described above, a transparent and viscous liquid composition is obtained, which exhibits the transparency and viscosity as described below.

[0034] Transparency

[0035] When measured at a temperature of, for example, from 4 to 25 °C, the composition exhibits a transparency of less than 100 NTU, preferably less than 75 NTU, more preferably less than 50 NTU, even more preferably less than 25 NTU. Preferably, the composition is a substantially isotropic and finely dispersed liquid cleaning composition. The term "substantially" preferably means "more than 90%", more preferably "more than 95%", even more preferably "more than 99%" of the composition.

[0036] Viscosity

[0037] The composition exhibits a viscosity in the range of 2,500 - 10,000 cps at 25°C. Preferably, when measured at 25°C, the composition exhibits a viscosity in the range of 3,000 - 9,000 cps, more preferably 3,500 - 8,500 cps, even more preferably 4,000 - 8,000 cps, still more preferably 4,000 - 7,000 cps. Viscosities throughout this specification are reported in cps. In SI units, 1000 cps is equivalent to 1 Pascal-second.

[0038] Inorganic salt

[0039] Preferably, the composition further comprises an inorganic salt selected from sodium chloride, sodium iodide, sodium bromide, sodium sulfate, potassium chloride, potassium iodide, potassium bromide, potassium sulfate, and mixtures thereof. More preferably, the inorganic salt is selected from sodium chloride, sodium sulfate, potassium chloride, potassium sulfate, and mixtures thereof. Even more preferably, the inorganic salt is selected from sodium chloride, potassium chloride, and mixtures thereof.

[0040] Preferably, the composition comprises 0.01 to less than 3% by weight, more preferably 0.05 to 2.5% by weight, even more preferably 0.1 to 2% by weight, further more preferably 0.5 to 1.5% by weight, and still more preferably 0.5 to 1% by weight of one or more of the above inorganic salts.

[0041] Non-soap anionic surfactant

[0042] Preferably, the composition further comprises a non-soap anionic surfactant. Non-soap anionic surfactants (such as those described below) are known to provide foaming and cleaning effects.

[0043] Preferably, the non-soap anionic surfactant is selected from alkyl sulfates, alkyl ether sulfates (AES), α-olefin sulfonates (AOS), and mixtures thereof. More preferably, the non-soap anionic surfactant is selected from alkyl sulfates, alkyl ether sulfates, and mixtures thereof. Even more preferably, an alkyl ether sulfate is used as the non-soap anionic surfactant in the composition.

[0044] Examples of alkyl sulfates that can be used as non-soap anionic surfactants in the composition include sodium lauryl sulfate (SLS), sodium myristyl sulfate, and mixtures thereof.

[0045] Examples of AES that can be used as non-soap anionic surfactants include anionic surfactants having the following general formula:

[0046] R1-(OR’) n -O-SO3 - M + , where:

[0047] R1 is a saturated or unsaturated C8-C 16 , preferably C 12 -C 14 alkyl chain; preferably, R1 is a saturated C8-C 16 , more preferably a saturated C 12 -C 14 alkyl chain;

[0048] R’ is ethylene; n is from 1 to 18; preferably from 1 to 15, more preferably from 1 to 10, even more preferably from 1 to 5,

[0049] M + is a suitable cation providing charge neutrality, preferably sodium, calcium, potassium or magnesium, more preferably the sodium cation.

[0050] Examples of AES that can be used as a non-soap anionic surfactant include sodium lauryl ether sulfate (SLES), sodium myristyl ether sulfate and sodium palmityl ether sulfate, and mixtures thereof. The preferred AES is SLES having 1-3 ethylene oxide units per molecule. More preferably, it is SLES having 1-2 ethylene oxide units per molecule.

[0051] Preferably, the composition comprises 1-25% by weight, more preferably 3-22% by weight, even more preferably 5-18% by weight, further more preferably 8-15% by weight, and still more preferably 10-12% by weight of a non-soap anionic surfactant, which may be selected from one or more of the non-soap anionic surfactants described above.

[0052] Stearic acid

[0053] Preferably, the composition further comprises stearic acid. It should be understood that stearic acid is an acid containing 18 carbon atoms in a chain which may be straight-chain or branched-chain; and may be saturated or unsaturated simultaneously.

[0054] Preferably, the stearic acid is selected from 10-hydroxy stearic acid (10-HSA), 12-HSA, petroselinic acid, conjugated linoleic acid and mixtures thereof. More preferably, the stearic acid is selected from 10-HSA, 12-HSA, petroselinic acid and mixtures thereof. Even more preferably, the stearic acid is selected from 10-HSA, 12-HSA and mixtures thereof. Further more preferably, the selected stearic acid is 12-HSA.

[0055] The composition comprises preferably 0.01-2% by weight, more preferably 0.05-1.5% by weight, even more preferably 0.1-1% by weight, further more preferably 0.25-0.75% by weight, and still more preferably 0.3-0.5% by weight of stearic acid.

[0056] Polymer

[0057] Preferably, the composition does not contain any viscosity - regulating polymers. Preferably, the composition contains from 0 to 0.1% by weight of a viscosity - regulating polymer.

[0058] However, if the composition contains viscosity - regulating polymers, they may be selected from water - soluble / or water - dispersible polymers, including gum sugars such as cellulose gums, microcrystalline cellulose, cellulose gels, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, methyl cellulose, ethyl cellulose, guar gum, karaya gum, tragacanth gum, gum arabic, acacia gum, agar gum, xanthan gum, and mixtures thereof; modified and unmodified starch granules and pre - gelatinized cold - water - soluble starch; emulsion polymers such as 28, 22 or Aqua SF1; cationic polymers such as modified polysaccharides, including cationic guar gums available from Rhone Poulenc under the trade names C13S, C14S, C17 or C16; cationic modified celluloses such as Polymer JR 30 or JR 40 from Amerchol; 3000, 3196, GPX 215 or GPX 196 from Hercules; synthetic cationic polymers such as 100, 280, 281 and 550 from Nalco; cationic starches such as 100, 200, 300 and 400 from Staley Inc.; cationic galactomannans such as the 800 series from Henkel, Inc.; LM - 200; and polyquaternium - Also suitable are high - molecular - weight polyethylene glycols, for example WSR - 205 (PEG 14M), WSR - N - 60K (PEG 45) and WSR - 301 (PEG90M).

[0059] pH of the composition

[0060] Preferably, the pH of the composition is in the range of 8.0 - 9.5, more preferably 8.5 - 9.0.

[0061] Water

[0062] Preferably, the composition contains 60 - 98% by weight, more preferably 65 - 95% by weight, even more preferably 70 - 90% by weight, still more preferably 75 - 85% by weight, and yet more preferably 80 - 85% by weight of water.

[0063] Preservative

[0064] Preferably, the composition further contains a preservative to protect the composition from the growth of potentially harmful microorganisms. Particularly preferred preservatives include hydantoin derivatives, propionates, various quaternary ammonium compounds, phenoxyethanol, imidazolidinyl urea, sodium dehydroacetate, and benzyl alcohol. The amount of the preservative is preferably in the range of 0.01% to 2% by weight, more preferably 0.1% to 1% by weight.

[0065] Emollient

[0066] The composition may further contain emollients such as stearyl alcohol, glyceryl monocastor oil, mink oil, cetyl alcohol, isopropyl isostearate, stearic acid, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecane - 2 - ol, isocetyl alcohol, eicosanol, behenyl alcohol, cetyl palmitate, silicone oils such as dimethylpolysiloxane, dibutyl sebacate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, butyl stearate, polyethylene glycol, triethylene glycol, lanolin, cocoa butter, corn oil, cottonseed oil, olive oil, palm kernel oil, rapeseed oil, safflower oil, evening primrose oil, soybean oil, sunflower oil, avocado oil, sesame oil, coconut oil, peanut oil, castor oil, acetylated lanolin alcohol, petrolatum, mineral oil, butyl myristate, isostearic acid, palmitic acid, isopropyl linoleate, lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate. Preferably, the emollient is added in a relatively low amount, such as 0 - 3% by weight and 1 - 2% by weight.

[0067] Optional ingredient

[0068] The composition may further contain a wide range of other optional components such as antioxidants, buffers, colorants, astringents, fragrances, humectants, conditioners, pH adjusters, skin soothers, and skin repair agents.

[0069] The present invention is further described by the following non - limiting examples.

[0070] Examples

[0071] Experimental protocol:

[0072] Preparation of the composition:

[0073] All the compositions shown in the table below were prepared using deionized water. Deionized water and potassium laurate powder (100%; Viva Corporation) were placed in a container in the amounts shown in the table below and thoroughly mixed using an overhead stirrer (Heidolph). Subsequently, the amphoteric surfactant CAPB (30%; Galaxy surfactants) and the non-soap anionic surfactant SLES (70%; Galaxy surfactants) were added to the container and completely homogenized. These two surfactants (SLES and CAPB) were obtained from their 70% and 30% concentrated stock solutions in proportionate amounts; such that the concentrations of these surfactants were as shown in the table below. Finally, salt (sodium chloride or potassium chloride; 100% laboratory grade) was added in the amounts shown in the table below.

[0074] Measurement of transparency

[0075] Once the composition was prepared, it was stored overnight at room temperature (∼24 ± 1 °C), and the turbidity of the sample was measured using a turbidimeter by the following method. For this purpose, the composition was filled into glass vials and air bubbles were ensured to be absent. The glass vial was placed inside the turbidimeter (TURBIQUANT T 1100IR) and measured. Once a stable reading was obtained, the measurement result was recorded. To measure the turbidity at a lower temperature, the composition was stored overnight in a refrigerator at 4 ± 1 °C. The composition was taken out of the refrigerator the next day and the turbidity measurement was carried out as described above.

[0076] Measurement of viscosity

[0077] Zero calibration (calibration without any rotor) was carried out each time the viscometer was used. The rotor RV-5 was fixed in the viscometer. The RPM and measurement time were set to 20 and 30 seconds respectively. The rotor was immersed in the test sample (composition) up to the mark mentioned on the rotor. As the measurement started, the rotor rotated inside the sample and the corresponding torque was measured, and the instrument displayed the calculated viscosity. The viscosity was measured after 30 seconds; and measured at room temperature (25 °C). For this purpose, a Brookfield RV viscometer and an RV-5 rotor were used to measure at 20 RPM for 30 seconds.

[0078] Examples 1 to 15 (according to the present invention) and Examples A to E (control):

[0079] Table 1: Examples 1 to 10 according to the present invention

[0080]

[0081]

[0082] (KLa: Potassium laurate)

[0083] Table 2: Examples 11 to 15 according to the present invention

[0084]

[0085] (KLa: Potassium laurate)

[0086] Table 3: Control examples

[0087]

[0088] (KLa: Potassium laurate; Precipitate: Observed precipitate material)

[0089] Examples 16, 17, F, G: Effect of containing an anionic surfactant compared with a non-ionic surfactant:

[0090] Prepare the compositions shown in Table - 4 below and record the transparency (as visually observed) at the end of 24 hours. In addition, the amount of foam produced is measured using the following procedure:

[0091] The composition is diluted 100 - fold with deionized water in a graduated cylinder (250 - ml capacity) (0.3 g of the product and 2.7 g of water). The graduated cylinder is closed with a glass lid and fixed in the instrument for foam generation. The graduated cylinder is rotated at 12.5 RPM for 40 revolutions to generate foam. Record the average of the foam produced in two graduated cylinders.

[0092] Table - 4

[0093]

[0094]

[0095] The data in Table 4 above show that, compared with the examples outside the present invention containing non - ionic surfactants (Examples F and G), the compositions according to the present invention containing the anionic surfactant SLES (Examples 16 and 17) provide better foaming and no impairment in terms of transparency.

Claims

1. A transparent liquid cleaning composition, comprising: a. Soap; and b. Amphoteric surfactant, wherein the soap and the amphoteric surfactant are present in a weight ratio of less than or equal to 2:1, wherein when measured at a temperature in the range of 4 - 25 °C, the transparency of the composition is less than 100 NTU; and wherein when measured at 25 °C, the viscosity of the composition is in the range of 2,500 to 10,000 cps; wherein the composition further comprises 1 to 25% by weight of a non - soap anionic surfactant selected from alkyl sulfates, alkyl ether sulfates, alpha - olefin sulfonates, and mixtures thereof.

2. The composition according to claim 1, wherein the composition comprises 0.01 - 7% by weight of soap.

3. The composition according to claim 1 or 2, wherein the soap is selected from salts of fatty acids having a carbon chain length of C8-C 14 and mixtures thereof.

4. The composition according to any one of claims 1-3, wherein the soap is selected from salts of fatty acids having a carbon chain length of C 10 -C 12 and mixtures thereof.

5. The composition according to any one of claims 1 - 4, wherein the soap is formed from the potassium salt of fatty acid.

6. The composition according to any one of claims 1 - 5, wherein the composition comprises 1 - 5% by weight of amphoteric surfactant.

7. The composition according to any one of claims 1 - 6, wherein the amphoteric surfactant is selected from betaines, sulfobetaines, cocoamphoacetates, and mixtures thereof.

8. The composition according to any one of claims 1 - 7, wherein the amphoteric surfactant is cocoamidopropyl betaine.

9. The composition according to any one of claims 1 - 8, wherein the composition further comprises 0.1 to less than 3% by weight of an inorganic salt selected from sodium chloride, sodium iodide, sodium bromide, sodium sulfate, potassium chloride, potassium iodide, potassium bromide, potassium sulfate, and mixtures thereof.

10. The composition according to any one of claims 1 - 9, wherein the composition further comprises an octadecanoic acid selected from 10 - hydroxystearic acid, 12 - hydroxystearic acid, petroselic acid, conjugated linoleic acid, and mixtures thereof.

11. The composition according to claim 10, wherein the octadecanoic acid is selected from 10 - hydroxystearic acid, 12 - hydroxystearic acid, and mixtures thereof.

12. The composition according to claim 11, wherein the octadecanoic acid is 12 - hydroxystearic acid.

13. The composition according to any one of claims 1 - 12, wherein the pH of the composition is in the range of 8.0 - 9.5.

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