Polyglycerol esters and their use

1. Polyglycerol partial ester having the structure of Formula (I)

with R 1 , R 2 and R 3 independent from each other, equal or different are selected from the group consisting of

—OH,

—OR 4 , with R 4 a linear, unsubstituted acyl radical with a chain length of from 16 to 22 carbon atoms with the proviso that the fatty acids obtained from the acyl radical by saponification bears an iodine value of smaller than 50,

a radical having the structure of general Formula (II)

with R 5 a radical having the structure of Formula (I) wherein one of R 1 , R 2 and R 3 being a direct bond to the oxygen of −OR 5 and with X a bivalent organic residue with from 2 to 34 carbon atoms and

—OR 5 , with R 5 as described above

wherein each molecule of the polyglycerol partial ester comprises at least one of each —OR 5 and a radical having the structure of Formula (II),

with the provisos that the polyglycerol partial ester comprises an HLB-value from 2 to 10 and that the polyglycerol obtained by hydrolysis or alcoholysis of the polyglycerol partial ester comprises an average degree of polymerization of from 2 to 8 and at least 1% of the polyglycerol comprises cyclic structures and that at least one R 4 is present in the polyglycerol partial ester.

2. Polyglycerol partial ester according to claim 1 wherein X is a bivalent, linear, unsubstituted alkyl radical with 2 to 12 carbon atoms.

3. Polyglycerol partial ester according to claim 1 wherein said ester has a molecular weight (Mn by GPC) of at least 2000 g/mol.

4. Polyglycerol partial ester according to claim 1 wherein the molar ratio of monocarboxylic acid component to dicarboxylic acid component is 2-20.

5. Polyglycerol partial ester according to claim 1 wherein the molar ratio of the dicarboxylic acid component to polyglycerol is from 0.1 to 1.0.

6. Polyglycerol partial ester according to claim 1 wherein said ester has a melting point of at least 25° C.

7. A method for the preparation of polyglycerol partial esters comprising the steps of

1.) esterification of

a) a polyglycerol mixture comprising an average degree of polymerization of from 2 to 8, and at least 1% of cyclic structures, with

b) at least one monocarboxylic acid comprising a carboxylic acid HOR 4 , with R 4 a linear, unsubstituted acyl radical with a chain length of from 16 to 22 carbon atoms with the proviso that the carboxylic acid or mixture of carboxylic acids bears an iodine value of smaller than 50,

2.) addition and further esterification with

c) at least one dicarboxylic acid having the structure of general Formula (IIb).

with X a bivalent organic residue with from 2 to 34 carbon atoms or mixtures thereof

with the proviso that the ratio by weight of polyglycerol mixture to the sum of monocarboxylic acid and dicarboxylic acid is in the range from about 0.11 to 1.

8. A polyglycerol partial ester concentrate wherein a solvent is present consisting of

A) at least 50 wt. % of at least one polyglycerol partial ester according to claim 1 ,

B) up to 50 wt. % of a solvent and optionally

C) 0.1 wt. % to 5 wt. % of a preservative,

wherein the wt. % refer to the total weight of the concentrate and the wt. % of all components sum up to 100 wt. %.

9. Polyglycerol partial ester according to claim 1 , wherein said ester has a melting point of at least 35° C.

10. Polyglycerol partial ester according to claim 1 , wherein said ester has a melting point of at least 40° C.

11. The method according to claim 7 , wherein said polyglycerol mixture comprises an average degree of polymerization of from 2.5 to 6.

12. The method according to claim 7 , wherein said polyglycerol mixture comprises an average degree of polymerization of from 3 to 4.5.

13. The method according to claim 7 , wherein said carboxylic acid or mixture of carboxylic acids bears an iodine value of smaller than 30.

14. The method according to claim 7 , wherein said carboxylic acid or mixture of carboxylic acids bears an iodine value of smaller than 25.