Title of Invention

COLOURING OF KERATINOUS FIBERS

Abstract

The invention provides for a process for the colouring of keratinous substrates comprising contacting the keratinous fibers sequentially with a solution/suspension of (a)0.5-25% of an iron salt at pH below 3 and(b)a colour developer selected from hydrolysable tannin or its breakdown products or derivatives or a mixture thereof obtained from a natural or synthetic source. where the sequence of contact is in any order.

Full Text

FORM - 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10 and Rule 13) COLOURING OF KERATINOUS FIBERS HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India The following specification particularly describes the invention and the manner in which it is to be performed. ORIGINAL 1052/MUM/2004 5-10-2004 GRANTED 23-1-2008 Technical Field: The present invention relates to compositions for changing the colour of keratinic fibers especially human hair. Background and Prior art: Presently the number of people wishing to have their hair coloured has increased. In order to obtain a uniform colour over the whole hair, permanent hair colours are more used than temporary and semi-permanent hair colours. These types of temporary and semi-permanent hair colour do not give any control to the consumer over the amount of colour deposited. Hence most people prefer the permanent hair colours. Permanent hair colour generally comes in two parts: a dye solution and a developer solution. Because of the damaging nature of current permanent dye treatments, most home colouring products come with a post treatment conditioner. The developing substances still most frequently used in hair dyeing compositions are 1,4-diaminobenzene (p-phenylenediamine) and 1-methyl-2,5- diaminobenzene (p-toluylenediamine). Colouring products need to be applied every four to six weeks since hair grows out of the scalp at the rate of approximately one half inch per month. Each colouring application causes damage to the hair, and that damage is cumulative. Use of these dyes can also cause allergenic reactions in some people in addition to damage to structure of hair fiber. 2 It would be desirable to develop a method and kit that minimizes the damage caused to hair by the coloring process. The present invention provides the potential benefits of an effective natural based hair darkening formulation. Melanin is a naturally occurring pigment present in hair and it is synthesised in melanocytes in the presence of the enzyme tyrosinase. Two different melanins are found in human hair, eumelanin and pheomelanin. While brown and black hair contain eumelanin, pheomelanin is found in red hair. Efforts have been made in the past to provide a hair dyeing process that mirrors the formation of the hairs" natural pigment, melanin. There have been several attempts to permanently colour hair using the black colour that is generated by using tannin and an iron salt. JP01090117 discloses the use of a complex containing iron (preferably ferrous) and an organic compound (preferably gallic acid) as a hair dye agent. JP63041414 discloses specifically the use of a complex of gallic acid with ferric iron (FeCI3). However, it talks about a premade complex of the two compounds along with a carboxyvinyl polymer to make it a black gelatinous substance that can be applied to hair. The delivery of a gallic acid - iron complex directly to hair in the form of a hair dye is well established in literature (JP61056119, JP60209513, JP60048916). 3 ALL THe above mentioned disclosures are different from the present invention as we have found that the delivery of iron and hydrolysable tannin and/or its breakdown products or derivatives such as gallic acid separately into hair is essential to provide a superior colour development as compared to the application of iron-gallic acid as a preformed complex. We have also identified a superior delivery system which has not been disclosed in any of the prior art. It is also known in literature to use a two step process as a hair darkening system (EP0394930, JP04208214 and EP0327345). It is also known that pretreatment of hair with a ferrous salt at a pH 3 - 6 in order to make the subsequent step of bleaching hair with hydrogen peroxide less damaging to hair and less irritating to skin. This invention also deals with the subsequent dyeing of hair with a colorant such as tannic acid or gallic acid which would react with iron to give the colour. This prior art distinctly refers to the use of only ferrous salts in the pH range of 3-6. However we have found that use of ferric salts are superior to ferrous salt especially when used at a pH of 3 or lower. 4 Description of the invention: According to the present invention there is provided a process of colouring keratinous fibers comprising: contacting the keratinous fibers sequentially with a solution/suspension of (a) 0.5-25% of an iron salt at pH below 3 and (b) a colour developer selected from hydrolysable tannin or its breakdown products or derivatives or a mixture thereof obtained from a natural or synthetic source, where the sequence of contact is in any order. According to a preferred aspect of the present invention there is provided a process of colouring keratinous fibers comprising: contacting the keratinous fibers sequentially with (a) 0.5-25% solution of a ferric salt at pH below 3 and (b) a non-alcoholic solution of a colour developer selected from hydrolysable tannin or its breakdown products or derivatives obtained from a natural or synthetic source, where the sequence of contact is in any order. It is particularly preferred that the keratinous fibers are washed between the two contacting steps. 5 According to another aspect of the present invention there is provided a kit for colouring keratinous fibers comprising: i. a solution/suspension comprising 0.5-25% by weight of an iron salt at pH below 3; ii. a solution/suspension of a colour developer selected from hydrolysable tannin or its breakdown products or derivatives obtained from a natural or synthetic source; iii. instructions for application. According to a preferred aspect of the present invention there is provided a kit for colouring keratinous fibers comprising i. a solution comprising 0.5-25% by weight of an ferric salt at pH below 3; ii. non-alcoholic solution colour developer selected from hydrolysable tannin or its breakdown products or derivatives obtained from a natural or synthetic source; iii. instructions for application. The delivery of iron solution is particularly enhanced by incorporating a solvent system having Hansen solubility parameter 5h between 10-30 and Sp between 5-15 and optionally along with a solvent having Hansen solubility parameters 8h 1-10 and 8p 10-25. The units for Hansen solubility parameter 5h and Sp reported in all places in this document is (MPa)1/2. 6 The solubility parameter has been defined as the square root of the cohesive energy density and describes the attractive strength between molecules of the material. Hansen assumed that the cohesive energy arises from the dispersive, permanent dipole-dipole interactions and hydrogen bonding forces and 8p = polar term and 8h = hydrogen bonding term. The data on solubility reported here were obtained from Brandrup, J. and Immergut, E.H., eds., Polymer Handbook, 3rd ed., John Wiley & Sons, New York, 1989. Detailed Description of the Invention: The present invention relates to a colouring system suitable for hair comprising sequential application of an iron salt provided at a pH below 3 and a colour developer selected from hydrolysable tannin or its breakdown products or derivatives obtained from a natural or synthetic source, where the sequence of contact is in any order. The colouring system of the invention can be suitably supplied in the form of a combination kit. Iron salt: The iron salt is a water soluble salt of iron. It is preferable to provide the iron salt predominantly in the ferric form. The salts is preferably selected from chloride or nitrate. The delivery of iron solution is particularly enhanced by incorporating a solvent system having Hansen solubility parameter 5h between 10-30 and Sp 7 between 5-15 and optionally along with a solvent having Hansen solubility parameters 5h 1-10 and 6p 10-25. Solvent having Hansen solubility parameter 5h between 10-30 and 5p between 5 -15 is preferably selected from alcohols with upto 4 carbon atoms for e.g. methanol, ethanol, propanol, butanol or their isomers, vicinal diols such as ethylene or propylene glycols. The delivery of iron is further enhanced by incorporating a solvent having Hansen solubility parameters 5h 1-10 and 5p 10-25 is preferably selected from carbonate derivatives of vicinal diols such as ethylene carbonate or propylene carbonate, acetonitrile etc. Reducing Agent: When the iron salt is a chloride salt of iron, enhanced colour is obtained when the keratinous fibers are contacted with a solution/suspension of the iron salt at a pH below 3, where said solution/suspension comprises 0.5 to 2% of a reducing agent. The reducing agent is preferably selected from one or more of metallic iron, sodium sulphite, sodium metabisulphite, sodium thiosulphate, sodium dithionite or ascorbic acid. When a reducing agent is present, enhanced colour is obtained when said solution/suspension is in a pH range of 2 to 3, preferably 2.8 to 3. 8 Colour developer: The source of colour developer is a hydrolysable tannin or its breakdown products or derivatives from a natural or synthetic source. The hydrolysable tannins suitable for the present invention are selected from gallic acid, tannic acid, catechins and polyphenols. The natural source of hydrolysable tannins is from gall nuts, Terminalia species for e.g. chebula, bellerica, arjuna etc, tea, Mucuna pruriens and other gallic acid rich sources. When the source of the hydrolysable tannin is from a natural source the extracts of the leaves, stem, seeds, flowers and/or fruits of the plant can be used for the purposes of the invention. The extract of the raw and dried material can be obtained by methods generally known to obtain an extract from a plant. Especially preferred are the seeds and leaves. It is preferred to use a non-alcoholic extract and preferably an aqueous extract. It is not essential to remove the solvent used for extraction. However, it is possible to completely remove the solvent by conventional methods used in the art and use the concentrated extract so obtained, especially when an alcohol is used for extraction. The level at which the hydrolysable tannins are incorporated is in the range 0.01 - 40%. Product form: Examples of suitable product forms include solutions, emulsions, microemulsions, gels, creams, sprays and lotions. 9 Other conventional ingredients such as surfactants, gelling/thickening agents, emollients, humectants, perfumes and preservatives may be incorporated to formulate the composition as desired. Method of Application on Hair: The present invention also relates to a method of colouring hair by a sequential treatment with the two component system that has been described. By sequential treatment is meant that the components are applied one after the other in any specific sequence. However, the preferred sequence is the application of iron salt first followed by application of the hydrolysable tannin and/or its breakdown products or derivatives. After the application of the solution of the iron salt the hair is preferably washed with water or shampoo or any suitable composition. It is preferred that the component system is present as a kit with clear instructions on the application of the kit components. It is preferable that each component is applied once, though repeated application is possible. While a single application of the components is sufficient for colouring, in a preferred embodiment, the entire process is repeated four times. The hair colouring achieved by the present method is permanent in nature. By permanent is meant that the colour will not be removed by water or conventional surfactants. The above method of darkening hair can achieve a dark shade of black. 10 The kit: The kit used in the present invention is a container selected from paper, wood and/or plastic packaging or metal plastic strips in which the individual ingredients, the iron salt and the hydrolysable tannin and/or its breakdown products or derivatives are packed separately. The instruction is in the form of printed information is provided on the packaging or on the strip or pouch containing the ingredients or as a separate leaflet. The instructions are in national or any local or regional language. Optionally, an applicator for supplying the solution may also be present in the kit. A pair of gloves suitable for use when applying the solutions may also be provided with the kit. The invention is further illustrated by the following non-limiting examples, in which parts and percentages are by weight unless otherwise specified. EXAMPLES Example 1: Demonstration of the effect of pH: White hair swatches were incubated in 3% ferric chloride for 2 hrs at room temperature. The hairs were then washed and incubated in 0.5% gallic acid solution or the natural tannin obtained from Terminalia chebula for 1 hr. The Terminal® chebula seeds were extracted in water at 8D°C. The other 11 treatments as indicated in Table 1 were maintained for comparison. The treatment of the iron salt was given at different pH for e.g. 2, 3 and 4. All the samples were washed well and the colour intensity was measured using a sigma scan software. The colour intensity was read on a 0-255 scale where 0 is pure black and 255 is pure white. The data are presented in Table 1. For all data that will be presented in the following tables a higher value indicates greater white colour whereas a lower value indicates a darker colour. Table 1 Composition Colour intensity pH 2 pH 3 pH 4 Control white hair 200 200 200 Ferric chloride 180 180 180 Galic acid 200 200 200 Natural tannin from Terminalia chebula 200 200 200 Ferric chloride followed by Galic acid 88 (Black) 110 (Brown) 129 (Brown) Ferric chloride followed by natural tannin from Terminalia chebula 85 (Black) 106 (Brown) 128 (Brown) The data presented in table 1 show that the selection of the pH to be below 3 for giving the iron treatment to the hair is significantly superior to that when it is done above the said pH. The source of the tannin whether it is synthetic such as galic acid or from a natural source such as Terminalia chebula extract the effect on the darkening of the hair is equally good. 12 Example 2: Demonstration of sequential addition vs. premixed complex: White hair swatches were incubated for 2 hrs at room temperature in the following solutions: a. 3% ferric chloride. b. 0.5% gallic acid c. 3% ferric chloride, followed by 0.5% gallic acid d. 0.5% gallic acid followed by 3% ferric chloride e. a combination of 3% ferric chloride and 0.5% gallic acid All the samples were washed well and the colour intensity was measured using a sigma scan software. The colour intensity was read on a 0-255 scale where 0 is pure black and 255 is pure white. Table 2 Composition Colour intensity Control (White hair) 172 Ferric chloride 172 Gallic acid 172 Ferric chloride followed by gallic acid (sequential) 92 Gallic acid followed by ferric chloride (sequential) 122 Premixed Ferric chloride + gallic acid 154 The data presented in Table 2 show that sequential addition of ferric chloride and gallic acid produce significantly better hair darkening than application of the premixed compounds. 13 Example 3: Effect of different ferric salts on colour development on hair: White hair swatches were incubated with solutions containing various ferric salts shown in Table 3 at 3% (w/v) levels for 4 hours. They were then washed and incubated in 0.5% gallic acid (w/v) solution for 1 hr. The results are presented in Table 3. All the samples were washed well and the colour intensity was measured using a sigma scan software. The colour intensity was read on a 0-255 scale where 0 is pure black and 255 is pure white. Table 3 Composition Colour intensity Control (White hair) 172 Ferric chloride followed by gallic acid 48 Ferric nitrate followed by gallic acid 86 Ferric citrate followed by gallic acid 141 Ferric tartarate followed by gallic acid 155 Ferric ammonium oxalate followed by gallic acid 112 Data presented in Table 3 show that different ferric salts have hair darkening effect to various degree and that ferric chloride being the most effective. Example 4: Effect of solvents satisfying Hansen solubility parameters according to the invention on colour development: White hair swatches were incubated in the following conditions for 2 hrs: i Solution containing 3% (w/v) ferric chloride prepared in water. 14 ii. Solution containing 3% (w/v) ferric chloride prepared using 20% Ethyl alcohol, iii. Solution containing 3% (w/v) ferric chloride prepared using 20% Methyl alcohol, iv. Solution containing 3% (w/v) ferric chloride prepared using 20% Isopropyl alcohol. The Hansen solubility parameter of the above mentioned solvents are as follows. 5h 5p Ethanol 19.4 8.8 Methanol 22.3 12.3 Isopropanol 16.4 6.1 Samples were washed with water and then incubated in 0.5% Gallic acid for 1 hr. All the samples were washed well and the colour intensity was measured using a sigma scan software. The colour intensity was read on a 0-255 scale where 0 is pure black and 255 is pure white. The data is presented in Table 4. Table 4 Treatment Colour intensity Control white 172 Aqueous ferric chloride followed by gallic acid 120 Ethanolic ferric chloride followed by gallic acid 102 Methanolic ferric chloride followed by gallic acid 102 Isopropanolic Ferric chloride followed by gallic acid 92 15 Data presented in Table 4 show that presence of the solvents which have a Hansen solubility parameter 8h between 10-30 and 8p between 5-15 enhance the colour development. In particular use of alcoholic ferric chloride enhances the colour development and that use of isopropanolic ferric chloride is superior to the other alcoholic extracts tested. Example 5: Effect of a combination solvents satisfying Hansen solubility parameters according to the invention on colour development: White hair swatches were incubated in 5% aqueous ferric chloride and ferric chloride prepared in a isopropanol which has a Hansen solubility parameter 6h 16.4 and Sp 6.1 for 1 hour with or without the addition of propylene carbonate (5h 4.1 and 5p 18) as a second solvent that satisfies Hansen solubility parameter in the range 5h 1-10 and 5p 10-25 on colour development was tested. This treatment was followed by treatment with 0.5% gallic acid for 15 minutes. Table 5 Treatment Colour intensity Control white hair 172 Aqueous ferric chloride in water followed by gallic acid 132 Isopropanolic ferric chloride followed by gallic acid 121 Isopropanolic ferric chloride containing propylene carbonate followed by gallic acid 110 16 Data presented in Table 5 show that incorporation of propylene carbonate has a significant effect in improving the hair colour development. Example 6: Formulation in the form of a gel: Ferric chloride was formulated as a gel whose composition is provided in Table 6. Hair swatches were exposed to gels containing 5% Ferric chloride for 2 hours, followed by treatment with 0.5% gallic acid for 15 minutes. Table 6 Gel composition (%wt) Ex 6a Ex 6b Ex 6c Ex6d Ferric chloride - 5 5 5 Isopropanol - - 25 25 Propylene carbonate - - - 15 Water 100 95 70 55 Hydroxyethyl cellulose 1.5 1.5 1.5 1.5 Colour intensity 172 111 97 85 The data presented in Table 6 show that the said components can be formulated in the form of a gel composition which gives good colour development. Example 7: Formulation in the form of a microemulsion: Ferric chloride was formulated as a microemulsion whose composition is provided in Table 7. Hair swatches were exposed to microemulsion containing 5% Ferric chloride (with or without additives) for 4 hours, followed by treatment with 0.5% gallic acid for 15 minutes. 17 Table 7 Microemulsion composition (%wt) Ex 7a Ex 7b Ex 7c Ex7d Ferric chloride - 5 5 5 Distilled water 42 37 35 25 Light liquid paraffin oil 34 34 26 5 C12E07 17 17 - 25 C12E03 - - 40 9 Caprylic acid 7 7 - 7 Isopropanol - - 9 4 Propylene carbonate - - - 20 Colour intensity 172 107 108 82 The data presented in Table 7 show that the said components can be formulated in the form of a microemulsion which gives good colour development. Thus the present invention provides for a novel, stable, safe and inexpensive colouring system comprising an iron salt at a pH below 3 and a hydrolysable tannin. 18 We Claim: A process of colouring keratinous fibers comprising: contacting the keratinous fibers sequentially with a solution/suspension of (a) 0.5-25% of a ferric salt at pH below 3 and (b) a colour developer selected from hydrolysable tannin or its breakdown products or derivatives or a mixture thereof obtained from a natural or synthetic source, where the sequence of contact is in any order. 2. A process of colouring keratinous fibers as claimed in claim 1, wherein said ferric salt is chloride or nitrate. 3. A process of colouring keratinous fibers as claimed in claim 2, wherein said ferric salt is chloride and said solution/suspension comprises 0.5 to 2% of a reducing agent. 4. A process of colouring keratinous fibers as claimed in claim 3, wherein said reducing agent is selected from one or more of metallic iron, sodium sulphite, sodium metabisulphite, sodium thiosulphate, sodium dithionite or ascorbic acid. 5. A process of colouring keratinous fibers as claimed in claim 1, wherein said colour developer is selected from hydrolysable tannin or its breakdown products or derivatives obtained from a natural or synthetic source is provided as a non-alcoholic solution. 19 6. A process of colouring kefatinous fibers as claimed in any of the preceding claims wherein said hydrolysable tannin is selected from gallic acid, tannic acid, catechins and polyphenols. 7. A process of colouring kefatinous fibers as claimed in any of the preceding claims wherein the natural soureof said hydrolysable tannin is selected from gall nuts, Terminalia species for e.g- chebula, bellerica, arjuna etc, tea, Mucuna pruriens and other gallic acid rich sources. 8. A process of colouring kefatinous fibers as claimed in any of the preceding claims wherein the keratinous fibers are washed between the two contacting steps. 9. A process of colouring kefatinous fibers as claimed in any of the preceding claims, wherein said iron salt is delivered using a delivery system comprising one or more solvents having Hansen solubility parameter 8h between 10-30 (MPa)1/2 and 8p between 5-15 (MPa)1/2. 10. A process of colouring keratinous fibers as claimed in claim 9, wherein said delivery system comprises a second solvent system comprising one or more solvents having a Hansen solubility parameters 5h 1-10 (MPa)1/2 and 8p 10-25 (MPa)1/2. 11. A process of colouring keratinous fibers as claimed in any one of the preceding claims substantially as hefeindescribed and illustrated with reference to the accompanying examples. 20 12. A colouring system for implementing said process of colouring keratinous fibers as claimed in claim 1 is provided as a kit comprising: i. a solution/suspension comprising at least 0.5-25% by weight of an iron salt at pH below 3; ii. a solution/suspension of a colour developer selected from hydrolysable tannin or its breakdown products or derivatives obtained from a natural or synthetic source; iii. instructions for application. 13. A colouring system for implementing said process of colouring keratinous fibers as claimed in claim 12 is provided as a kit comprising: i. a solution comprising 0.5-25% by weight of an ferric salt at pH below 3; ii. non-alcoholic solution colour developer selected from hydrolysable tannin or its breakdown products or derivatives obtained from a natural or synthetic source; iii. instructions for application. Dated this 3rd day of October 2005 Dr.Sanchita Ganguli Of SMajumdar&Co Applicant"s Agent

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1052-mum-2004-correspondence 1(24-5-2006).pdf

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1052-MUM-2004-CORRESPONDENCE(8-2-2012).pdf

1052-mum-2004-correspondence(ipo)-(29-8-2007).pdf

1052-mum-2004-form 1(5-10-2004).pdf

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1052-mum-2004-form 18(24-5-2006).pdf

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1052-mum-2004-form 2(granted)-(23-1-2008).pdf

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