# Patent

## Title
Alkoxylated citrate polyesters

## 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.

## Background
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 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'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:




R1 is alkyl having 6 to 24 carbon atoms, or mixtures thereof;

R2 is —(CH2CH2O)x—CH2CH2 

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:




R1 is alkyl having 6 to 24 carbon atoms, or mixtures thereof;

R2 is —(CH2CH2O)x—CH2CH2 

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—(CH2CH2O)x—CH2CH2—OH

x is an integer ranging from 8 to 75;

and

(c) a fatty alcohol having R16 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—(CH2CH2O)n—CH2CH2—OH

x is an integer ranging from 8 to 75;
and
(c) a fatty alcohol having R116 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 R1 is alkyl having 6 to 20 carbon atoms.
In a preferred embodiment R1 is alkyl having 8 to 12 carbon atoms.
In a preferred embodiment R1 is alkyl is alkyl having 6 to 8 carbon atoms.
In a preferred embodiment R1 is alkyl is alkyl having 10 to 20 carbon atoms.
In a more preferred embodiment R1 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—(CH2CH2O)x—CH2CH2—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
C6H14O
102.2


 7
1-Heptanol
enanthic alcohol
 111-70-6
C7H16O
116.2


 8
1-Octanol
caprylic alcohol
 111-87-5
C8H18O
130.2


 9
1-Nonanol
Pelargonic alcohol
 143-08-8
C9H20O
144.3


10
1-Decanol
capric alcohol
 112-30-1
C10H22O
158.3


11
1-Undecanol

 112-42-5
C11H24O
172.3


12
1-Dodecanol
lauryl alcohol
 112-53-8
C12H26O
186.3


13
1-Tridecanol

 112-70-9
C13H28O
200.4


14
1-Tetradecanol
myristyl alcohol
 112-72-1
C14H30O
214.4


15
1-Pentadecanol

 629-76-5
C15H32O
228.4


16
1-Hexadecanol
cetyl alcohol
36653-82-4
C16H34O
242.5


17
1-Heptadecanol 
margaryl alcohol
 1454-85-9
C17H36O
256.5


18
1-Octadecanol
stearyl alcohol
 112-92-5
C18H38O
270.5


19
1-Nonadecanol

 1454-84
C19H40O
284.5


20
1-Eicosanol
arachidyl alcohol
 629-96-9
C20H42O
298.6


21
1-Henei cosanol

15594-90-8
C21H44O
312.6


22
1-Docosanol
behenyl alcohol
 661-19-8
C22H46O
326.6


23
1-Tricosanol

 3133-01-5
C23H48O
340.6


24
1-Tetracosanol
Lignoceryl
 506-51-4
C24H50O
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.

## Claims

1. A polyester made by the esterification reaction of:
(a) citric acid having the following structure:




(b) a water soluble diol having the following structure:


HO—(CH2CH2O)x—CH2CH2—OH


wherein:
x is an integer ranging from 8 to 75;

and
(c) a fatty alcohol having the structure R1OH
wherein:
R1 is alkyl having from 6 to 24 carbon atoms, or mixtures thereof.

2. A polyester of claim 1 wherein x is 8.

3. A polyester of claim 1 wherein x is 10.

4. A polyester of claim 1 wherein x is 50.

5. A polyester of claim 1 wherein x is 75.

6. A polyester of claim 1 wherein R1 is alkyl having 6 to 20 carbon atoms.

7. A polyester of claim 1 wherein R1 is alkyl having 8 to 12 carbon atoms.

8. A polyester of claim 1 wherein R1 is alkyl having 6 to 8 carbon atoms.

9. A polyester of claim 1 wherein R1 is alkyl having 10 to 20 carbon atoms.

10. A polyester of claim 1 wherein R1 is a mixture of alkyl one group having 8 to 10 carbon atoms and the second having 18 to 24 carbon atoms.

11. 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 having the following structure:




(b) a water soluble diol having the following structure:


HO—(CH2CH2O)n—CH2CH2—OH


wherein:
x is an integer ranging from 8 to 75;

and
(c) a fatty alcohol having the structure R1OH
wherein;
R1 is alkyl having from 6 to 24 carbon atoms, or mixtures thereof.

12. A process of claim 11 wherein said effective conditioning concentration ranges from 0.1% to 20% by weight.

13. A process of claim 11 wherein x is 8.

14. A process of claim 11 wherein x is 10.

15. A process of claim 11 wherein x is 50.

16. A process of claim 11 wherein x is 75.

17. A process of claim 11 wherein R1 is alkyl having 6 to 20 carbon atoms.

18. A process of claim 11 wherein R1 is alkyl having 6 to 8 carbon atoms.

19. A process of claim 11 wherein R1 is alkyl having 10 to 20 carbon atoms.

20. A process of claim 11 wherein R1 is a mixture of alkyl one group having 8 to 10 carbon atoms and the second having 18 to 24 carbon atoms.