Liquid, adhesion-promoting additive and process for its preparation

1. A polyester resin, comprising a polyester which comprises as esterified polymer units:

at least one of an unsaturated dicarboxylic acid and an unsaturated polycarboxylic acid; and

at least one of an alkoxylated diol and an alkoxylated polyol of the formula (I)

R—O(CH 2 CH 2 O) a (CH 2 CHCH 3 O) b —H  (I)

wherein

R=tricyclodecanedimethanol, 1,2-propanediol, cyclohexanedimethanol and neopentyl glycol

a=0 to 20;

b=0 to 20;

with the proviso that a+b≧1;

wherein said polyester is a liquid at 23° C. and a pressure of 101 325 Pa.

2. The polyester resin according to claim 1 , wherein the polyester resin is free of a polyester comprising any of bisphenol A, B, C, F or derivatives thereof.

3. The polyester resin according to claim 1 , wherein the at least one of an unsaturated dicarboxylic acid and an unsaturated polycarboxylic acid is an unsaturated dicarboxylic or poly-carboxylic acid selected from the group consisting of citraconic acid, fumaric acid, itaconic acid, maleic acid and mesaconic acid.

4. The polyester resin according to claim 1 , wherein the polyester further comprises as an esterified polymer unit, an acid selected from the group consisting of an aromatic, aliphatic or cycloaliphatic monocarboxylic acid, an aromatic, aliphatic or cycloaliphatic dicarboxylic acid, an aromatic, aliphatic or cycloaliphatic polycarboxylic acid and a phosphoric acid.

5. The polyester resin according to claim 1 , wherein the at least one of an alkoxylated diol and an alkoxylated polyol is alkoxylated with an agent selected from the group consisting of ethylene oxide, propylene oxide, 1,2-butene oxide, 1,2-heptene oxide, 1,2-octene oxide, 1,2-nonene oxide, 1,2-undecene oxide, 1,2-dodecene oxide, 4-methyl-1,2-pentene oxide, styrene oxide, butadiene monoxide, isoprene monoxide, cyclopentene oxide and/or 2-ethyl-1,2-butene oxide.

6. The polyester resin according to claim 1 , wherein a molar ratio of the alkoxylated diol or polyol to the dicarboxylic or polycarboxylic acids is from 1:2 to 2:1.

7. The polyester resin according to claim 1 , wherein an acid number of the polyester, determined according to DIN EN ISO 2114, is from 1 to 150 mg KOH/g.

8. The polyester resin according to claim 1 , wherein an OH number of the polyester, determined according to DIN 53240-2, is from 1 to 200 mg KOH/g.

9. The polyester resin according to claim 1 , wherein the polyester comprises as esterified polymer units:

at least one of ethoxylated or propoxylated tricyclodecanedimethanol; and

a mixture of fumaric acid and/or maleic acid and adipic acid.

10. The polyester resin according to claim 9 , wherein the ethoxylated or propoxylated tricyclodecanedimethanol comprises at least one selected from the group consisting of ethoxylated or propoxylated

3,8-bis(hydroxymethyl)tricyclo[5.2.1.0 2,6 ]decane, ethoxylated or propoxylated

4,8-bis(hydroxymethyl)tricyclo[5.2.1.0 2,6 ]decane and ethoxylated or propoxylated

5,8-bis(hydroxymethyl)tricyclo[5.2.1.0 2,6 ]decane.

11. An adhesion-promoting additive comprising the polyester resin according to claim 1 .

12. A formulation comprising the polyester resin according to claim 1 .

13. The formulation according to claim 11 , further comprising at least one auxiliary or adjuvant selected from the group consisting of an inhibitor, water, an organic solvent, a neutralizing agent, a surface-active substance, an oxygen scavenger, a radical scavenger, a catalyst, a light stabilizer, a color brightener, a photosensitizer, a thixotropic agent, an anti-skinning agent, a defoamer, an antistat, a thickener, a thermoplastic additive, a dye, a pigment, a flame retardant, an internal release agent, a filler and a propellant.

14. The polyester resin according to claim 1 , wherein a=5 to 12.

15. The polyester resin according to claim 1 , wherein b=5 to 12.

16. The polyester resin according to claim 1 , wherein R=tricyclodecanedimethanol.