Abstract:
The present invention has as its objective a series of citrate polyesters that have based upon guerbet alcohols reacted with citric acid, and crosslinked by diols. 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.

Description:
RELATED APPLICATIONS 
     This application is a divisional application of Ser. No. 12/584,407 filed Oct. 5, 2009, now U.S. Pat. No. 8,148,569, which in turn claims priority to and benefit of U.S. Provisional Application No. 61/279,259 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 liquidity, and outstanding feel when applied to the skin. 
     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 C1 to C18 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 guerbet alcohols reacted with citric acid, and crosslinked by diols. These polymers have a very low viscosity when one considers the molecular weight, and are ideally suited to personal care applications due to the unique feel. 
     The present invention also has an objective a process for treating hair and skin with the guerbet 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 guerbet alcohols reacted with citric acid and a diol crosslinker. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to a polyester that conforms to the following structure: 
                                
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 a mixture of between 15 and 60%
 
                                
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) HO—(CH 2 ) 3 —OH, a natural diol made from corn;
 
(c) octyldodecanol conforming to the following structure:
 
     
       
                 
         
             
             
         
      
     
     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) HO—(CH 2 ) 3 —OH, a natural diol made from corn;
 
(c) octyldodecanol conforming to the following structure:
 
     
       
                 
         
             
             
         
      
     
     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. 
     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: 
     
       
                 
         
             
             
         
      
     
     Example 2 
     1,3 propane Diol 
     1,3 propane diol is a natural product derived from corn. DuPont Tate &amp; Lyle Bio Products&#39; 1,3-propanediol is a colorless and highly pure glycol derived from a sustainable and renewable corn sugar fermentation process. Corn-derived 1,3-propanediol is the perfect glycol solution for formulations and ingredient solvents where non-petroleum based ingredients are desired, and can replace propylene glycol and butylene glycol. Benefits of corn-derived 1,3-propanediol include its purity, lack of irritation and sensitization, and environmentally friendly nature. This natural diol conforms to the following structure:
 
HO—(CH 2 ) 3 —OH
 
     In the present invention this material provides a linking group that is (a) natural, (b) free of polyoxyethylene and polyoxypropylene compounds and their inherent ether groups and lack of natural origin, and (c) are easily reacted into the polymer matrix. 
     Example 3 
     Octyldodecanol 
     Octyldodecanol is a Guerbet alcohol commercially available from a variety of sources including Cognis. 
     
       
                 
         
             
             
         
      
     
     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 octyldodecanol (Examples 3). 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 1,3 propane diol (Examples 2). 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 Acid   Diol   Guerbet               Example 1   Example 2   Example 3           Example   Grams   Grams   Grams   a value                                10   111   22   867   1       11   120   36   844   2       12   134   57   809   5       13   144   71   785   10       14   148   77   775   15       15   150   81   769   20                    
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 of cushion and play tome. 
     The compounds are of exceptional interest in the personal care applications where gloss, rheology that accommodates spreading and odor are critical. 
     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.