Abstract:
The present invention has as its objective a series of citrate polyesters that have based upon fatty alcohols reacted with citric acid, and crosslinked by water soluble diols, resulting in polymers with improved water solubility. These polymers are ideally suited to personal care applications due to their unique feel delivered from aqueous solution or emulsions.

Description:
RELATED APPLICATIONS 
     This application is a continuation in part of Ser. No. 12/586,709, filed Sep. 28, 2009 now U.S. Pat. No. 8,158,114 which claims priority to and benefit of U.S. Provisional Application No. 61/271,259 filed Jul. 20, 2009, the disclosure of which is incorporated herein for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to a series of polymeric citrate esters that have unique improved compatibility with water, are themselves liquid, and have an outstanding feel when applied to the skin from aqueous formulations. 
     BACKGROUND OF THE INVENTION 
     Citric acid is a common material of natural origin. The structure is: 
                                
CAS Registry Number: 77-92-9
 
CA Index Name: 1,2,3-Propanetricarboxylic acid, 2-hydroxy-
 
     Citric acid is made by fermentation; using cultures of  Aspergillus niger  are fed on a sucrose or glucose-containing medium. 
     Citric acid is one of a series of compounds involved in the physiological oxidation of fats, proteins, and carbohydrates to carbon dioxide and water. This series of chemical reactions is central to nearly all metabolic reactions, and is the source of two-thirds of the food-derived energy in higher organisms. Krebs received the 1953 Nobel Prize in Physiology or Medicine for the discovery. The series of reactions is known by various names, including the citric acid cycle, the Krebs cycle, and the tricarboxylic acid cycle 
     Citrate esters are known. They conform to the following structure: 
                                
The esters are made by the reaction of fatty alcohols with citric acid.
 
     U.S. Pat. No. 4,292,192 issued to Hooper, et al. teaches that Detergent bars for personal washing are given a deodorant property by including an ester of citric acid. The ester may be an acetyl derivative. The amount of ester used will be in the range of from about 0.3% to about 3%. Examples of the esters are triethyl citrate and acetyl tributyl citrate. 
     U.S. Pat. No. 2,122,716 describes long chain esters of citric acid, e.g., tridodecyl citrate, which have been used as plasticizers for resinous compositions. 
     U.S. Pat. Nos. 3,239,555 and 3,241,992 disclose bis-citric acid esters made by esterifying the acid groups with C 1  to C 18  alcohols and coupling the esters with dibasic acids. Such esters are useful as plasticizers for plastics. 
     U.S. Pat. No. 3,251,792, the acid groups of citric acid are esterified with alkyl, aryl, cycloalkyl and haloaryl alcohols and the hydroxyl group is esterified with a carbonyl compound. Such compounds are used as stabilizers for polypropylene. 
     U.S. Pat. No. 5,089,658 issued Feb. 18, 1992 to Elmore et al, is directed to citric acid esters. In one aspect, this invention pertains to citric acid esters, which contain at least one primary or secondary hydroxyl group. In another aspect, this invention relates to citric acid esters, which are reactive diluents. In still another aspect, this invention pertains to citric esters, which are pigment dispersants. The citric ester compositions of this invention are useful as reactive diluents for high solids thermosetting coating composition and as pigment dispersants for use in thermosetting coatings 
     U.S. Pat. No. 4,868,236 to O&#39;Lenick discloses a guerbet citric ester and polymers thereof useful in plastic lubrication. 
     None of these patents provide polyester derivatives of mixed fatty esters of citrate as envisioned by the present invention. 
     THE INVENTION 
     Objective of the Invention 
     The present invention has as its objective a series of citrate polyesters that have based upon fatty alcohols reacted with citric acid, and crosslinked by water soluble diols, selected from the group polyoxyethylene, polyoxyalkylene and combinations thereof. These polymers have a very low viscosity when one considers the molecular weight, and are ideally suited to personal care applications due to their unique feel, when delivered from aqueous solution. 
     The present invention also has an objective a process for treating hair and skin with the fatty acid derived citrate polyesters. 
     Other objectives will become clear as one reads the specification and claims herein. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a polyester made by the reaction of a mixture of fatty alcohols reacted with citric acid and a water soluble diol crosslinker. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to a polyester that conforms to the following structure: 
                                
R 1  is alkyl having 6 to 24 carbon atoms, or mixtures thereof;
 
R 2  is —(CH 2 CH 2 O) x —CH 2 CH 2  
 
x is an integer ranging from 8 to 75;
 
a is an integer ranging from 0 to 20.
 
     Another aspect of the present invention is a process for conditioning hair and skin which comprises contacting the hair or skin with an effective conditioning concentration of a polyester that conforms to the following structure: 
                                
R 1  is alkyl having 6 to 24 carbon atoms, or mixtures thereof;
 
R 2  is —(CH 2 CH 2 O) x —CH 2 CH 2  
 
x is an integer ranging from 8 to 75;
 
a is an integer ranging from 0 to 20.
 
     In a preferred embodiment said effective conditioning concentration ranges from 0.1% to 20% by weight. 
     The products of the present invention are made by the esterification reaction of 
     (a) citric acid conforming to the following structure: 
     
       
                 
         
             
             
         
      
     
     (b) a water soluble diol conforming to the following structure:
 
HO—(CH 2 CH 2 O) x —CH 2 CH 2 —OH
 
x is an integer ranging from 8 to 75;
 
and
 
     (c) a fatty alcohol having R 1 6 to 24 carbon atoms, or mixtures thereof. 
     Another aspect of the present invention is a process for conditioning hair and skin which comprises contacting the hair or skin with an effective conditioning concentration of a polyester made by the esterification reaction of: 
     (a) citric acid conforming to the following structure: 
     
       
                 
         
             
             
         
      
     
     (b) a water soluble diol conforming to the following structure:
 
HO—(CH 2 CH 2 O) n —CH 2 CH 2 —OH
 
     x is an integer ranging from 8 to 75; 
     and 
     (c) a fatty alcohol having R 1 16 to 24 carbon atoms, or mixtures thereof Preferred Embodiments 
     In a preferred embodiment a is an integer ranging from 1 to 20. 
     In a preferred embodiment a is an integer ranging from 3 to 10. 
     In a preferred embodiment a is 10. 
     In a preferred embodiment a is 15. 
     In a preferred embodiment 10 said effective conditioning concentration ranges from 0.1% to 20% by weight. 
     In a preferred embodiment x is 8. 
     In a preferred embodiment x is 10. 
     In a preferred embodiment x is 50. 
     In a preferred embodiment x is 75. 
     In a preferred embodiment R 1  is alkyl having 6 to 20 carbon atoms. 
     In a preferred embodiment R 1  is alkyl having 8 to 12 carbon atoms. 
     In a preferred embodiment R 1  is alkyl is alkyl having 6 to 8 carbon atoms. 
     In a preferred embodiment R 1  is alkyl is alkyl having 10 to 20 carbon atoms. 
     In a more preferred embodiment R 1  is a mixture of alkyl one group having 8 to 10 carbon atoms and the second having 18 to 24 carbon atoms. 
     EXAMPLES 
     Example 1 
     Citric Acid 
     Citrate is an item of commerce commercially available from a variety of sources including Pfizer. It conforms to the following structure: 
     
       
                 
         
             
             
         
      
     
     Examples 2-5 
     Water Soluble Diols 
     The water soluble diols useful in the present invention are items of commerce sold by many suppliers and conforming to the following structure:
 
HO—(CH 2 CH 2 O) x —CH 2 CH 2 —OH
 
x is an integer ranging from 8 to 75.
 
     Example 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Example 
                 x 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 2 
                 8 
               
               
                   
                 3 
                 10 
               
               
                   
                 4 
                 50 
               
               
                   
                 5 
                 75 
               
               
                   
                   
               
             
          
         
       
     
     In the present invention this material provides a linking group that is (a) water soluble, (b) based upon polyoxyethylene and polyoxypropylene compounds, and (c) are easily reacted into the polymer matrix. 
     Example 6-24 Fatty Alcohols 
     Fatty alcohols commercially available from a variety of sources including Condea. 
     
       
         
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                 CAS registry 
                 Molecular 
                   
               
               
                 Ex 
                 IUPAC name 
                 Common name 
                 number 
                 formula 
                 MW 
               
               
                   
               
             
             
               
                  6 
                 1-Hexanol 
                 caproic alcohol 
                  111-27-3 
                 C 6 H 14 O 
                 102.2 
               
               
                  7 
                 1-Heptanol 
                 enanthic alcohol 
                  111-70-6 
                 C 7 H 16 O 
                 116.2 
               
               
                  8 
                 1-Octanol 
                 caprylic alcohol 
                  111-87-5 
                 C 8 H 18 O 
                 130.2 
               
               
                  9 
                 1-Nonanol 
                 Pelargonic alcohol 
                  143-08-8 
                 C 9 H 20 O 
                 144.3 
               
               
                 10 
                 1-Decanol 
                 capric alcohol 
                  112-30-1 
                 C 10 H 22 O 
                 158.3 
               
               
                 11 
                 1-Undecanol 
                   
                  112-42-5 
                 C 11 H 24 O 
                 172.3 
               
               
                 12 
                 1-Dodecanol 
                 lauryl alcohol 
                  112-53-8 
                 C 12 H 26 O 
                 186.3 
               
               
                 13 
                 1-Tridecanol 
                   
                  112-70-9 
                 C 13 H 28 O 
                 200.4 
               
               
                 14 
                 1-Tetradecanol 
                 myristyl alcohol 
                  112-72-1 
                 C 14 H 30 O 
                 214.4 
               
               
                 15 
                 1-Pentadecanol 
                   
                  629-76-5 
                 C 15 H 32 O 
                 228.4 
               
               
                 16 
                 1-Hexadecanol 
                 cetyl alcohol 
                 36653-82-4 
                 C 16 H 34 O 
                 242.5 
               
               
                 17 
                 1-Heptadecanol  
                 margaryl alcohol 
                  1454-85-9 
                 C 17 H 36 O 
                 256.5 
               
               
                 18 
                 1-Octadecanol 
                 stearyl alcohol 
                  112-92-5 
                 C 18 H 38 O 
                 270.5 
               
               
                 19 
                 1-Nonadecanol 
                   
                  1454-84 
                 C 19 H 40 O 
                 284.5 
               
               
                 20 
                 1-Eicosanol 
                 arachidyl alcohol 
                  629-96-9 
                 C 20 H 42 O 
                 298.6 
               
               
                 21 
                 1-Henei cosanol 
                   
                 15594-90-8 
                 C 21 H 44 O 
                 312.6 
               
               
                 22 
                 1-Docosanol 
                 behenyl alcohol 
                  661-19-8 
                 C 22 H 46 O 
                 326.6 
               
               
                 23 
                 1-Tricosanol 
                   
                  3133-01-5 
                 C 23 H 48 O 
                 340.6 
               
               
                 24 
                 1-Tetracosanol 
                 Lignoceryl 
                  506-51-4 
                 C 24 H 50 O 
                 354.7 
               
               
                   
                   
                 alcohol 
               
               
                   
               
             
          
         
       
     
     General Procedure 
     To a suitable reactor equipped with heating and an ability to distill off water is added the specified number of grams of citrate acid (Example 1), finally is added the specified number of grams of the fatty alcohol (Examples 6-24). The reaction mass is heated to 150-160° C. and water is distilled off. As the reaction proceeds, the batch clears and free citric acid is reacted out. The reaction mass is kept at this temperature until the acid value becomes vanishingly low. Next is added the specified number of grams of the specified water soluble diol (Examples 2-5). The reaction mass is heated to 180-190° C. and water is distilled off. The reaction mass is kept at this temperature until the acid value becomes vanishingly low. The reaction mass is cooled and used without additional purification. 
                                                                                       Citric                           Ex-   Acid   Diol   Diol   Alcohol   Alcohol           ample   Grams   Example   Grams   Example   Grams   “a”                                25   384   2   104   6   408   0       26   1344   3   888   7   1044   5       27   2304   4   2112   8   1820   10       28   3264   5   3776   9   2736   15       29   4224   2   2184   10   3792   20       30   384   4   192   11    688   0       31   1344   5   1416   12   1674   5       32   2304   2   1144   13   2800   10       33   3624   3   2368   14   4066   15       34   4224   4   4032   15   5472   20       35   384   5   236   16   968   0       36   1344   2   624   17   2304   5       37   2304   3   1628   18   3780   10       38   3264   4   3072   19   5396   15       39   4224   5   4956   20   7152   20       40   384   2   104   21   1248   0       41   1344   3   888   22   2934   5       42   2304   4   2112   23   4760   10       43   3264   5   3776   24   6783   15                    
Ex means example in the table above.
 
     Products that are of the present invention were low order liquids that range from very dry easily spread (a is 1-10), to medium viscosity (a is 12-15), to viscous liquids with a lot an outstanding skin feel when applied from aqueous solution or emulsion. 
     The polymers that have high an “x” value that is above 50 have a water loving domain that is solid at room temperature. Lower “x” values result in liquid water loving domains. The polymers that have a fatty alcohol group above 18 carbon atoms have solid fatty domains. The fatty alcohol groups C12 and below provide liquid oil soluble domains. 
     The balance between the domains results in softer or harder waxes, and more or less water solubility. It is this property of adjusting the polymer to meet the need that has resulted in what we call High Definition Polymers (HDP). 
     While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth hereinabove but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains.