Compositions suitable for the treatment of hair comprising chelants and methods for reducing oxidative hair damage

Abstract

The present invention relates to hair care compositions comprising an oxidizing agent and chelants having a log K CuL /log K CaL ratio calculated at pH 10 of at least 3.20 wherein log K CuL is the common logarithm of the Conditional Stability Constant of said chelant with Cu 2+ and log K CaL is the common logarithm of the Conditional Stability Constant of said chelant with Ca 2+ . Suitable chelants are diamine-N,N′-dipolyacids or monoamine monoamide-N,N′-dipolyacids. The compositions according to the present invention contribute to reducing the oxidative damage sustained by a keratinous fiber such as hair during bleaching, dyeing, perming or other oxidative treatments. Especially preferred diamine dipolyacid is ethylenediamine-N,N′-disuccinic acid (EDDS).

1 . A composition suitable for treating hair comprising: 
 a) an oxidizing agent; and    b) a chelant (L) having a log K CuL /log K CaL  ratio calculated at pH 10 of at least about 3.20, wherein log K CuL  is the common logarithm of the Conditional Stability Constant of said chelant with Cu 2+  and log K CaL  is the common logarithm of the Conditional Stability Constant of said chelant with Ca 2+ ; and    wherein said chelant is present at a level of at least about 0.1% by weight of the composition.    
   
   
       2 . A composition according to  claim 1 , wherein said chelant has a Hydrogen Peroxide Decomposition Ratio (% Loss) of less than about 3.5% as measured by the Hydrogen Peroxide Decomposition Ratio Measurement Protocol.  
   
   
       3 . A composition according to  claim 1 , wherein said chelant is capable of forming a hexadendate complex with Cu 2+ .  
   
   
       4 . A composition according to  claim 1 , wherein the pH of the composition is between about 8 and about 12.  
   
   
       5 . A composition according to  claim 1 , wherein said composition is in the form of an oil-in-water emulsion.  
   
   
       6 . A composition according to  claim 1 , wherein said composition is in the form of a thickened aqueous solution.  
   
   
       7 . A composition according to  claim 1 , wherein said oxidizing agent is present at a level of from about 0.1% to about 40% by weight of said composition and is selected from water-soluble oxidizing agents and mixtures thereof.  
   
   
       8 . A composition according to  claim 7 , wherein said oxidizing agent comprises hydrogen peroxide.  
   
   
       9 . A composition according to  claim 1 , wherein said chelant is present at a level of from about 0.1% to about 10% by weight of said composition.  
   
   
       10 . A composition according to  claim 1 , further comprising at least one oxidative hair dye precursor.  
   
   
       11 . A method of treating hair, said method comprising the steps of: 
 i) contacting hair with a first composition comprising a chelant (L) having a log K CuL /log K CaL  ratio calculated at pH 10 of at least about 3.20; and    ii) contacting hair with a second composition comprising an oxidizing agent immediately after step i);    wherein log K CuL  is the common logarithm of the Conditional Stability Constant of said chelant with Cu 2+  and log K CaL  is the common logarithm of the Conditional Stability Constant of said chelant with Ca 2+ ; and    wherein said chelant is present at a level of at least about 0.1% by weight of the first composition.    
   
   
       12 . A method of treating hair, said method comprising the steps of: 
 i) contacting hair with a first composition comprising an oxidizing agent;    ii) contacting hair with a second composition comprising a chelant having a log K CuL /log K CaL  ratio calculated at pH 10 of at least about 3.20; and    iii) contacting hair with a third composition comprising a second oxidizing agent;    wherein steps i) and iii) are separated by at least 1 day and step ii) does not take place immediately before step iii);    wherein log K CuL  is the common logarithm of the Conditional Stability Constant of said chelant with Cu 2+  and log K CaL  is the common logarithm of the Conditional Stability Constant of said chelant with Ca 2+ ; and    wherein said chelant is present at a level of at least about 0.1% by weight of the second composition.    
   
   
       13 . A kit for dyeing hair comprising a first and a second compositions packaged in different containers, wherein said first composition comprises an oxidizing agent and said second composition comprises an oxidative dye precursor, wherein the resulting mixture of said first and second compositions is a composition according to  claim 10 .  
   
   
       14 . A method of dyeing human hair, said method comprising the steps of: 
 i) mixing the first and second composition of a kit according to  claim 13;     ii) contacting hair with the mixture obtained on step i);    iii) massaging said mixture into hair;    iv) retaining said mixture on the hair for an amount of time sufficient for mixture to dye the hair;    iv) rinsing off said composition with water.    
   
   
       15 . A method of treating hair according to  claim 11 , wherein said first composition is not rinsed off the hair before said second composition is applied to the hair.  
   
   
       16 . A kit for treating hair comprising: 
 i) a first separately packaged composition comprising a chelant (L) having a log K CuL /log K CaL  ratio calculated at pH 10 of at least about 3.20, wherein log K CuL  is the common logarithm of the Conditional Stability Constant of said chelant with Cu 2+  and log K CaL  is the common logarithm of the Conditional Stability Constant of said chelant with Ca 2+ ; and 
 wherein said chelant is present at a level of at least about 0.1% by weight of the first separately packaged composition; and  
   ii) a second separately packaged composition comprising an oxidizing agent.